It’s true that Vega has wall techniques and chances are you’ll be flying over each others head a lot. However, that’s not the way to go when being the counter-aggressor. Now you don’t have to rely on being defensive, which I really don’t think it’s the way to go against Vega at all (though I’m only speaking when using aggressive-capable fighters). If you see a wall technique coming up, I noticed that it is frequently the one where Vega reaches overhead and does the slash-swipe,(sorry for not knowing the names. I’m serious, I only played Ken, and just now Adon, so I really don’t know anything of other fighters) I counter this with a FADC after absorbing the slash-swipe blow. Forward or Backwards is purely up to you, both are safe, but forward (or whichever takes you closer to Vega) tends to have more punishment opportunities because you’re closer, of course. This should be already in your arsenal against Vega, and a good way to integrate this into the counter-aggressor theme is by baiting him to frequently chase you with it (and you’ll be surprised how many Vega’s rely on that move and not the drill-like one, or the suplex grab). Do poke combos (block strings work too) or achieve an untechable knockdown. Before wake-up, LKTooth which will bait them to wall-technique chase you, and 6/10 times it will be the overhead claw strike. Of course, don’t overly rely on this because some of them just jump back to their corner and what not, especially ones who’ve been punished by it a few times. Other than that, only use specials during poke combos (HKJK good at finishing combo/block strings because frame advantage) or clearly open punishment. Keep the heat, but aim for your hits to be blocked because it really baits them to do a slide or the backflip kick which are punishable with just about anything that isn’t intensive. HP -> HKRJ will do for backflip kick, and substitute HP for LK -> HKRJ or LP -> LK -> L/M/HKRJ. This is the essence of counter-aggressive play. Create heat, make them think they have something to punish (especially Vegas), then punish their follow up. Of course, there are countless ways of doing this, which I religiously use, but it’s like a work of art more than science, and it’s easier by just doing in then saying it. What I can offer is mixing this tactic with FADC baits before wake up, empty jump ins and outs before wake up (especially if you’ve been utilizing MKCrossup, which is pretty safe if used appropriately), and various levels of JTooth (consistent empty ones confuse them). Not to echo, but to expand, this is the role of counter-aggression. Aggressive, but aim to be blocked most of the time, and force them to be aggressive and counter their aggressiveness because you already see it coming. As far as punishing with anti-airs, I’m not all to positive. With Ken, good-ol’-faithful Ultra 1 did very nicely against anything, especially Vega’s Ultra I (or any Ultra for that matter), which, by using these tactics, a very easy set-up. Not sure how Adon’s Ultra II will fare, but it’s worth a shot.
–After applying pressure and gaining a knockdown (techable or not), dash up (if you have time) before wake up and then immediately do HKJT. More times than not, they’ll try a grab or poke of some sort, which 9/10 you’ll get the hit. If blocked, you get a free grab, or you can simply neutral jump MK into a poke combo if you know any, or a RJ.
—Pay attention to Vega’s pattern and fit in as many MKCrossups you can. They enable good combo opportunities, which might inevitably end with a knockdown (which really sets Vega’s off balanced, especially if you try to screw up their charge by switching sides), and will ultimately keep them on their toes because they’ll get the impression you’re going to be aggressive from there. Of course, you won’t, go back to counter-aggression.
----Chase Vega’s handsprings if you’re close. From there it’s extremely variable. I’m not sure to recommend this because you have to be a fairly good reader to use this properly. Following the handspring is risky because there is so many options for Vega which makes it harder for you to decide exactly what to do. I don’t really have a problem if I found a pattern. So look for a pattern and try to counter it. But remember, escape after it, or sometimes, come right back somehow (most likely a HKJT, which I dub this tactic as Boomerangin’). My usual routes are a crHK (among many other options) if they are grab-heavy, a MKCrossup, or block then punish if it’s a backflip kick. If they use a wall technique, either chase for pressure (but you have to be a good reader and creative for an effective follow up) or return to the standard tactics. Lastly, don’t follow if the Vega is crPoke-heavy. His crPokes are very long and hard to punish, and to escape, once in them. If you can counter them, or if they normally poke once (Focus here if so), then be confident and do so.
-----CAUTION: I’m not sure if it’s all forms, or just one, or some, but a RJ is stuffed by throw if close enough. Everyone probably knows that, but just reemphasizing.