First and foremost, this is purely a cosmic farming build. I'm not trying to suggest this is the best for pure numbers. I'm putting this out there purely because people have been asking about what I'm doing to not get frmolished in Cosmic Level Terminals and Patrols since the biggest patch ever. The secret? I'm basically using the same build as I did a week prior to the BUE.

This is a direct transfer of the build from the Marvel Heroes Forums.

• Combat Surge, for the purpose of this build you're going to need/want the serum built from meteor kick and vibranium bash.
• Impenetrable, we don't want Indestructible Shield taking up bar space. This makes it activate automatically.
• Cutting Edge, gives our shield throws a bleed effect. This is essential for damage layer and making our Furry Mane. You'll take it and like it, soldier.
• Serum Rush, this is where we get our damage. Every serum point spent is going to make our cooldowns hit hard enough to be on par with most other heroes, post BUE. If you don't utilize this, don't expect TTK to be competitive. On the flip side, you're forced to learn a rotation, instead of just button smashing. Sorry.
• Inspiration, is another trait we're taking for it's utility, but also because it activates automatically when we use our signature. So it saves bar space and empowers. Just salute, click this trait and move on.

Infinity System

• Power Gem -- Superhuman & Strike Through
  With my current gear the way it is, the one thing Cap's current kit is lacking? Damage. I try to make up for that a little bit here by focusing entirely on getting some much needed Brutal Strike Chance and Brutal Strike Damage. 
• Reality Gem -- Potency
  Potency is really the only choice and as you get more Infinity Points, this should be something you eventually max out. A very big chunk of Cap's damage is garnered through his, admittedly broken, signature.
• Soul Gem -- Fighting
  Once you've maxed out Brutal Strike, Brutal Damage, and got the other necessary point bonuses in other categories? Fighting. Every additional 25 points you earn, go here.
• Space Gem -- Gravity Well
  Another "point dump" here. We want to get the bonus to medkit, it's essential. I tested with 100 and 150, but unfortunately with Cap's current kit the way it is? We need additional damage far too much. We have to put those points elsewhere. So take your medkit bonus and move along quickly.
• Time Gem -- Temporal Loophole
  Loophole was only worth the points until approximately 18%, at which point it was showing significant diminishing returns. Your gear will determine where it does for you, but then switch to your movement talent of choice. I went with Time Flux in the end, because I found myself never really needing my dash cooldowns to be faster thanks to Aerial Assault in combat.
• Mind Gem -- Mental Focus
  So the reason I cover this Gem last is because your choice here is going to be entirely gear dependant. I've invested a lot of the in-game money, in to getting very near-perfect gear rolls on most of my Cap's gear. This translates in to 57% crit. I'm already hitting the point where Crit chance is dimenished. So my points are best spent in Crit Damage, then dumping all my additional points in to fighting.
• PROCs - All
  One thing you'll notice, is that I put at least one point in to every proc. This is purely for the additional damage. Cap's kit is hurting for damage. So any potential additional source of it is worth a minor investment. However if you're just starting out? These can be skipped. They're purely optional. When seconds start to matter to you? Go get those nodes, but remember not to to point dump in to them at the sacrifice of Fighting.

• Vibranium Bash, is my nuke and generator thanks to Combat Surge.
• Meteor Kick, another double duty ability as it's a generator and execute thanks to Combat Surge.
• Torqued Shield Throw , serves mostly as filler. I like to switch my talents to Coordinated Strikes in heavy trash areas, then use this as trash clear at times when the bleed from cutting edge isn't as useful due to things dying quickly for the damage layer payoff.
• Airborne Assault, is your basic positioning and filler attack. Can be used to trigger your midtown signets if you use those.
• Shield Bash, pure filler really. Benefits nicely from heavy deflect ratings on Cap's gear and his main stat (Strength).
• Shield Bounce / Shield Toss, I'm using both depending on the situation. Bounce puts my damage layer on everything around me, while Toss does a bit more single target damage. I was using Toss on my Dummy attempts, but found Bounce favorable in Midtown.
• At the suggestion of a guild mate, I am currently testing my build with the combination of Stunning Backflip (replacing Torque Shield Throw or Shield Bash), AirborneAssault and a Midtown Signet. If it pays off, I'll amend and post some vids.

Basic Rotation:

1. Airborne Assault: [ With or without Serum, it's primary purpose is the vulnerability at the beginning. ]
2. Shield Bounce: [ Buffed Bleed applied. ]
3. Meteor Kick: [ Build Serum to Max! ]
4. Star-Spangled Strike: [ Cooldown is reduced, you're buffed, let's kick some Nazi butt!]
5. Shield Bash or Torque Shield Throw: [ If you're surrounded by trash mobs, use Torqued Shield Throw, if you're alone with the Boss, then shield bash him in the kisser. ]
6. Vibranium Bash: [ This is your nuke, so have this going at all times. It'll keep you constantly generating Serum to Spend.]

Alternative Rotation:

1. Airborne Assault: [ With or without Serum, it's primary purpose is the vulnerability at the beginning. ]
2. Shield Bounce: [ Buffed Bleed applied. ]
3. Meteor Kick: [ Build Serum to Max! ]
4. Star-Spangled Strike: [ Cooldown is reduced, you're buffed, let's kick some Nazi butt!]
5. Shield Bash or Torque Shield Throw: [ This now depends entirely upon which skill you've replaced with Backflip! ]
6. Backflip: [ Use this whenever you want to get out of bad, move away from combat..etc, then Airborne Assault back to the action! ]
7. Vibranium Bash: [ This is your nuke, so have this going at all times. It'll keep you constantly generating Serum to Spend.]

Okay. So now a little explanation here. This is not a button mash build, folks. You are going to be in the middle of bulked up Trash and Bosses that can actually kill you now. So follow "Cap's Advice," stick and move. Use your dash for it's CC removal. Use Airborne Assault to reposition. Never worry about using Airborne Assault to move around, it's purpose is application of Vulnerbility -and- Movement (both for a trigger and surviving). Since you'll be moving around, there's significant time to build up 5-10 serum between the attacks that actually matter. You'll want 5+ serum for Torque Shield Throw, Shield Bash, routinely. If you have extra time, use it for Airborne Assault, just because it's there for utility doesn't mean we can't make it hurt more if we have time. However --ALWAYS-- have 10 Serum for Star-Spangled Strike.

• Skrull's Mighty Hammer, this has +1 Fighting and is enchanted with Critical Hit Rating.
• Stark Industries Support Armor, this has +1 Fighting and is enchanted with Health.
• Invaders Photograph, this has +1 Fighting and is enchanted with Health.
• Boondockers, this has +1 Fighting and is enchanted with Health.
• The Captain's Mask, this has +1 Fighting and is enchanted with Health.
• Xavier's School for Gifted Youngsters Class Ring or Sling Ring of the Kamar-Taj (physical), the Slingring is good for TTL, Class Ring is a little better for TTK.

Not much to say here. I'm sporting Cap's personal uniques in all slots but the first. I am maximizing my DMG, CHR/CDR and attribute rolls. On my gear, I'm accepting just about anything else on the peripheral stats, but I do make an effort to have to keep health, attack speed and spirit cost rolls in the yellow.

Prior to the update, I used a X-Men Uniform, and Goat Mask. After just a handful of Cosmic Doctor Doom runs and hours of Cosmic Patrols I ditched the any hero uniques, because his own uniques just offered way too much TTL, without seeming to lose ANYTHING from TTK. I want to state again, I am not focusing on TTK on stand-still dummies. If that is your goal, then the Any Hero uniques will serve you well.

:Artifacts:

1. Sabertooth's Furry Main
2. Crossbone's Teaching Credentials 
3. Sacred White Gorilla Necklace
4. Gem of the Kursed

There are some really good alternatives to these depending upon whether you want more TTK or more TTL, with one noteable exception. Sabretooth's Furry Mane tested so far above everything else for me, that I found it to be performing significantly better than anything else I own. Even without a cosmic affix, it was performing better than anything else I had. So if you have one of these to spare or if Cap is your main? Put it on him.

Update [08/26/17]: Sabertooth's Fury Mane is currently testing better for Cap than any other artifact in the game. Still. However, as you progress along in your gearing a number of Cosmically Enhanced versions of some artifacts pull ahead of non-cosmic versions. For example a cosmic version of Captain America's Star pulled ahead of a non-Cosmic Gorilla Necklace (One of the only artifacts that I've yet to get a cosmic version of, sadly).

:Legendary:

• Savage Axes
• Shield of Perseus
• Excalibur

At first, I was dying constantly in anything that hit back. So I went immediately to old faithful Shield of Perseus. After about two hours, I got the "feel" of things. At that point, I first tried out an old Excalibur that I had in my bags and suddenly was having no trouble at all. By the end of last week, I had put my Savage Axes back on. While I still die occasionally in Patrols ( I swear, mostly due to not being able to see the Boss indicators or the invisible trash ), once I got the feel of how how much damage that I could soak before I needed to retreat it was really fine with the Savage Axes. In Cosmic Danger Room, I stick to the Shield of Perseus.

:Relics:

• Atlantis, I use these 99% of the time on Cap.
• Lemuria, is really a good solution for folks with lower end gear or those who don't like the movement aspect of ... y'know... not standing in bad.

:Medallion:

• S.H.I.E.L.D. Agent Medallion, nuff said.
• Onslaught Medallion, not optimal really, but if you don't have the Agent Medallion maybe.
• Red Skull Medallion, I tinkered with this too on the dummy and it helped for TTK, but I took it off pretty much as soon as things began hitting back.

:Insignia:

• Captain America
• Spider-Man
• Eric O'Grady
• Mockingbird

I'm using a Cap Insignia, with CHR and CDR. However, what you will actually want? Is CHR and your choice of utility stat. If that's CHD, Health, Attack Speed...etc, pick what you need. Just remember Crit Hit Rating and Brutal Hit Rating are point for point the "Best in the Business" post BUE.

 

- Phil Coulson, if you have him? Use him. In fact use him as an active team up. Seriously. He's actually doing almost as much damage as a number of playable heroes.
- Falcon, has the same passive bonuses as Coulson. But Coulson has additional summons that give a major bump to TTL. Old skool Falcon seems to be in need of a revamp.
- Domino, use if you're going to stick to passive boost, but at least for my setup Domino was almost the same as having no team up at all.

:Pet Stats:

• Health
• Spirit
• Critical Damage
• Crit Rating & Attack Speed on hit for 12 seconds (15 second cooldown)
• Fighting

:Synergies:

• Ant-Man
• War Machine
• Cable
• Wolverine
• Squirrel Girl
• X-23
• Moon Knight
• Elektra
• She-Hulk
• Nightcrawler or Cyclops ( If you need XP for ANY REASON on any character, use Cyclops. No other synergy gives you enough of a bonus to overcome the XP bonus. )