I've posted about this before, but I still believe it to be true.
Scorpion is only really a problem for two reasons, and the problems aren't him (though nerfing his face in might be the easiest answer).
The real issues as I see em,
1. Movement in IGAU sucks donkey dong. Every character in the game other than Scorpions feels sluggish and ill-responsive as far as general movement is concerned. This is mostly because of the dash system implementation. And even Scorpion only feels like he isn't sluggish because his teleport generally removes his need to ever use the shitty dash system.
2. Anti-air options in IGAU similarly perform fellatio on crossbred equines. When Scorpion is hoping about, jumping in at you, jumping over you, almost everyone seems limited to "just defending" this inherently gives Scorp the ability to control the pacing of the match.
I think everyone who is bitching about him being hard to block needs to man up and play some MVC3. If you find a move that takes some 23 frames to hit "hard to block" good luck blocking mix-ups in a game where you have mere frames to react due to the cross-up happening much closer to the impact frame of a secondary attack (from an assist, or the point character). Not to mention that the teleports in MVC actually allow for real mix-ups. Scorpions tele does not, will not, EVER mix you up. It ALWAYS hits you from the opposite side he starts from, and more importantly can be ducked NO MATTER WHAT. I understand that the meta is more complicated than that, the same can be said about any move, and a complex meta does not dictate in and of itself whether a thing is too good or not.
What would I change? Most importantly (and this isn't just about fixing Scorpion) give d2 a universal change by removing the top 1/3-1/2 of the characters hitbox during the move. Doing so would make it so a D2 generally (almost always) won over a jump-in attack.
The other thing I would consider changing is making it so you can block during a dash. You couldn't cancel the dash, but during the dash frames you could still chose to block an attack, doing this would let you approach him and or make space from him without being punished for dashing. (It would also drastically change how zoning works in the game, and maybe even make it so DS could be 'un-nerfed')
Neither are happening I expect, so unless Scorp gets some adjustments... he should probably be banned.
TL: DR - Scorpion isn't the real problem, the shitty movement and AA mechanics are. Since these mechanics probably aren't changing, Scorpion probably should.