Vega is sometimes considered top tier in Super Street Fighter 2 Turbo (ST), or at least in the top of the 2nd tier. He’s fast, has many good pokes, a good slide, and his off-the-wall attack is versatile and powerful. In keeping with the design philosophy of HD Remix, Vega is only barely weaker now, and he has harder competition all around from other characters.
The Wall Dive
Vega’s wall dive no longer knocks down. In ST, after you get knocked down by the wall dive, Vega can do it again as you get up and force you do block a tricky cross-up. If you get hit again, he can do it again, and so on. Vega is actually perfectly capable of winning without this abusive, repeatable tactic, so losing it isn’t crippling.
Note that if Vega hits you out of the air with the wall dive, of course you will be knocked down (same as any air-to-air attack). And his izuna drop (throw) from his wall dive still knocks down, so if you get hit by either of those things, he can threaten one more wall dive as you get up, but even if that hits, you’ll be able to stop his next attempt much more easily.
While it is possible to combo a low strong after you hit with a wall dive now (because the dive doesn’t knock down), it’s position-dependent. You usually end up hitting a little to high with the wall dive to actually combo a followup, but with good timing, you can. I didn't specifically intend this combo to work, but adding more delay at the end of the wall dive would mean you could hit back Vega too often, even when he hits you. Overall, I think it's much preferable to fight against a Vega who sometimes gets an extra hit of low strong, rather than a Vega that traps you in a knockdown loop.
Note that years after Street Fighter HD Remix's release, some of the biggest tournaments in the US for ST have come down to Vega's repeated knockdown wall dives, including Evolution 2013 and two different tournaments at Evolution 2014.
n ST, Vega can “store” his flip kick command. First, charge down/back, then hold back. You can hold back as long as you like and you can still do the flip kick by taping forward+kick. It’s so hard for some characters to actually get close to Vega, that he really doesn’t need what amounts to a (Guile) flash kick anti-air while walking backwards. A couple Japanese top players as well as several Americans all requested that this be removed, so it is. The only command for Vega’s flip kick attack is now charge down/back, then forward + kick. I personally never even used this technique, and really don't think he needed it to win.
Fake Wall Dive
Vega does get one new toy to play with: the fake wall dive. First, execute the wall dive (charge down, up + kick), and after Vega touches the wall, press kick again. Vega will hang for a moment, then drop directly down. This is marginally useful in avoiding Ken’s fierce dragon punch or Blanka’s vertical roll.
An earlier version of the fake wall dive allowed Vega to slightly steer whether he dropped forward or away (rather than just straight down) and it dropped down something like three times as fast as it does now. After some players complained that it was too powerful in a playtest, I gave my usual response of asking for someone to beat me with it, or at least make me afraid of it. I chose Ryu and took on all comers, which included many well-known Evolution tournament players. No one beat me one single game with their Vega. In fact, no one beat me even a single round. I was not remotely afraid of the fake wall dive. I’m not telling you this as a form of bragging, I’m just letting you know how balancing happens.
Why was I not afraid? Because doing repeated fake wall dives left my opponents with no real advantage over just sitting there and doing nothing. Yes it’s tricky in that you never know which wall dive will have teeth and which will be fake, but I mostly ignored it and jump roundhoused (or air hurricane kicked) at them anyway.
And yet one thing they demonstrated was important. James Chen showed that in ST with Vega vs. Cammy, if Vega does blocked low jab, cancels into off-the-wall (opposite wall) then holds back to stay away, Cammy can still cannon spike him. In other words, he cannot use the wall dive to turn his low jab into a safe runaway tool in ST. But the same setup in HD Remix with the fake wall dive did allow him to be safe vs. the cannon spike. Even though no one demonstrated anything in real gameplay, the mere potential for more Vega runaway was enough to show that we needed to weaken the move.
It turns out, the move had to be slowed down significantly to prevent it from being completely safe in the sort of situation I explained above. Since then, I’ve seen no one able to run away with the fake wall dive, but it can occasional trick the opponent into attacking at the wrong time, so it seems about right.
A few top players have wondered if Vega is too strong, even still. Time will tell of course, but he does seem about right to me. His most abusive tactic is weakened, and he has a (kind of slow) fake wall dive in return. But what’s much more relevant is the field of characters he must now face.
Zangief is more able to fight him than ever. Guile used to have no real answer to Vega repeatedly sliding. (I wonder if anyone has any tournament matches of me doing something like 12 slides in a row vs. Choi’s or Jeron’s Guile in tournaments.) But now Guile has 2 answers: roundhouse flash kick and the new overhead. Cammy, Fei Long, and T.Hawk all got huge boosts and are just more threatening overall to Vega and to everyone else.
That said, Vega is still Vega. His speed, range, and wall dive keep him in the game, but he should be less dominant than in ST due to his adversaries being more equipped to fight him than before.