Easy one. All she needs is for her powers to be cheaper. For as little damage as she gets from her purple, it should be at most one AP more than MBW. At most. Possibly just have it the same, and have the damage as a compensation for not having the best stun in the game as her other power. Bring Payback Mission down to maybe 10 black or so.
Next: Mystique
Let’s add a fun, strategic (and highly annoying for the coders) wrinkle into her Shapeshift. Instead of the countdown tile, she’ll get a repeater tile. However, while it’s operational, you control the other team’s turn. The amount of purple AP it drains per turn and the period of the tile are both dependent upon the ability level.
Next up is another fun punching bag - X-Force Wolverine.
Green gets a big damage bump and/or is targetable.
Yellow is similar to Wasps where if he’s holding a certain amount of yellow, a 1 or 2 turn countdown spawns each turn (if one doesn’t already exist) and gives him a burst of health.
Next: Archangel… please!!
3* Captain Marvel: Red destroys strike and attack tiles at upper levels.
Next: 3* Doctor Octopus
3* Doc Ock: Lower blue AP cost to 9, lower green AP cost to 10 and make stun so its not random.
Next: 3* Punisher
3* Punisher
Green - The Punisher unloads his arsenal. In addition to creating strike tiles, Punisher ruthlessly dismantles the enemies attack destroying all enemy strike tiles dealing damage for each one.
Black - Buff attack tile strength at Max level.
Next: 2* Captain America
For 2* Cap:
Simpler Fix: Reduce the costs of his Red by One, his Blue by 2, and his Yellow by 4.
More Complicated Fix: Give him a fun new Yellow that speaks to his flavor as a ‘classic’ cap:
FROM THE ICE (Passive)
Captain America seems to fall fighting, but his superhuman stamina keeps him alive. If Captain America is reduced to (10% of health), place a 2-turn countdown that restores (60% hp), and stun Captain America for 2 turns.
Additional covers can increase health thresholds on either end…kind of like a 2-star equivalent to the Phoenix rez…
Next : 3* Squirrel Girl.
For Squirrel Girl, remove the cap on her purple damage so it’s boosted for all opposing special tiles on the board. Change yellow to:
The Bigger They Are: 9AP
Create a 4 turn countdown tile and end the turn. While the countdown tile is on the board, reduce all enemy match and ability damage by the percentage of the opponent’s health remaining, to a minimum of 1. (i.e. a full health enemy has all damage reduced to 1, a half health enemy has damage reduced by 50%, etc).
Next: Howard the Duck
Howard the Duck: Blue does damage on removed enemy special tiles.
Next: Kraven the Hunter.
Kraven was already done.
Hard to come up with another buff that doesn’t change the mechanics of his abilities. Maybe something with invisibility (as he’s stalking his prey) on blue? When you activate it, he goes invisible for 1 to 3 turns.
Next: the 5* that needs fixing the most, Banner Hulk.
5* hulk - in hulk form he collets AP when he makes a move. Possible increase team damage on his green smash (might not be needed if he collects ap).
next up - 3* gambit
3* Gambit
Black Cost 6AP – Gambit uses his skills to steal for his own advantage. Places a 3 turn countdown timer which on expiry gives Gambit 4 purple and 3 red AP. However, if these tiles are matched before expiry, Gambit is caught and loses 1AP from purple and red or a random colour if no AP in those colours. At max level tile is fortified.
Red (Passive) – if at the start of the turn there are no charged tiles on the board, create 1 charged tile in a random colour in addition to existing powers.
Next: 3* Bullseye
3* Bullseye
Purple- Does additional damage for each friendly tile targeted. Can target up to 4. Targetted tiles are destroyed and gen AP.
Black- additional passive whenever Bullseye makes a match, creates 1 friendly and enemy strike tile. (Apparently I like powers that make enemy tiles)
I would like to revisit Banner, give him something better before he transforms too. I would also remove his auto match all together, but thats just me.
Next: Spiderwoman (Jessica Drew)
Superwoman
Reduce red cost to 12.
Next: 4* Carol
4* Carol
Ummm, she’s already T10 as it is, but I’ll bite.
Green: In addition to existing abilities, starting at 3 covers it steals 1AP (3 at max covers) from the enemy’s weakest colored pool.
While we’re redesigning the dream team, how about Coulson?
The topic creator said it could be a nerf or a buff.
I thought it would be interesting to see what people would want changed with someone who may arguably be best in the 4* tier.
Stinking autocorrect lol.
Coulson:
Yellow power - sniper either gains AP for destroyed tiles or does not destroy friendly tiles. Either works for me. I just hate it when his sniper tile destroys a whole bunch of countdowns 
Next:Colossus
I actually like Colossus’ kit, he’s just so darned expensive. Reduce all his AP costs by 2 across the board and he suddenly become an interesting 3-star and a dangerous tank.
Next: 4-star Rocket & Groot
I’ll take Colossus…
Buff
Black - Fastball bring it down to 12 tiles versus 13
Red - I like the “in front” part of the power, but i’d buff enemy damage to 1/2 the target damage (So if 2650 is target, team takes 1325)
Yellow - Countdown tile does damage once the timer runs out, i’d say ~600 at power level 3 for a 166. Increases by 40% for each power level since the timer gets longer.
EDIT @Dormammu beat me to it, so please continue 