The official source has their detailed explanations

Hawkeye

[Old] 1/1 - On Reveal: If you play a card here next turn, +2 Power

[Change] …next turn, +2 Power. ->...next turn, +3 Power.

Hulkbuster

[Old] 3/4 - On Reveal: Merge this card with a random friendly card at this location.

[Change] 3/4 -> 3/5

Vision

[Old] 5/7 - You can move this each turn.

[Change] 5/7 -> 5/8

Captain Marvel

[Old] 5/6 - At the end of the game, move to a location that wins you the game. (If possible)

[Change] 5/6 -> 4/5

Absorbing Man

[Old] 4/3 - On Reveal: If the last card you played has an On Reveal, copy its text. (if it's in play)

[Change] 4/3 -> 4/5

Personal thoughts:

That's a lot of cards that don't get a lot of use, huh? I'm curious about the Vision and Captain Marvel changes. In theory, they're reflections of the current Lockdown meta which got even stronger with Legion. In practice, however, there's still the constant danger of Professor X, which neither of them can help with, and Jeff is still the one counter to that (aside from a lucky play)

Frankly, I think Vision would benefit much more from a Cost drop than a Power buff. A round 5 card that can move is just too much of a late gamble.

Hulkbuster definitely got shafted after Phoenix Force came out, but I'm curious about its re-emergence as a Deadpool or Multiple Man combo. Personally I've felt that one was always a bit too tight, but its a solid play whenever it happened.

Now Absorbing Man and Hawkeye are both interesting changes. Can't say I ever see those, aside from a desperate ditch in a Hazmat deck from AM, while Hawkeye is basically a fodder card for starters until people get literally any other 1-cost. The possibility of being a Bounce addition is there, now let's see if it happens in practice.

This is also a personal curiosity as none of those cards were ever in my rotations, aside from trying Captain Marvel a few times. At least the possibility of the whole thing shaking up the location breakers is interesting.

Thoughts?