After playing MVC3 a lot and watching it a lot... I might be crazy in saying this but I really feel that MVC3 is one of the more "balanced" fighting games around. I would compare this game's balance to something like Tekken 5 DR/Tekken 6 BR, where you have some tiers and some "match ups" where certain character is at an advantage/disadvantage but overall every character/team has a chance if it's set up correctly.
Also characters like Hulk/Haggar have their match ups too. Like they are good with assists backing them up and against characters who like to get in. Haggar especially strives on player mistakes as he likes to control space with his pipe and leads to good meterless damage. Not to mention that these character's main strength are their invulnerable moves, which means that a rushdown team comes in backed up by an assist (like Akuma's assist) and Hulk does Anti-Air Gamma Charge ~ H, combo and hyper killing off 2 characters. Same for Haggar, he can do Lariat into super and probably X Factor for the double character kill and after that it's one mix up into the finisher.
There is a reason why invulnerable assists are given to a very few select cast members, those who aren't that great on point. I would say it's more of a balancing thing that characters like Hsien-Ko, Haggar, Hulk aren't that great on point.
Really wanted to see Justin body the south in person lol.