Yeah Vegeta is stout. Aside from his assist though hes Ryu-esque.. He doesn't have anything that makes you stand up and take notice or is flashy, but everything he has is really solid and he does everything well. Make's for a strong character.
I think the initial "hes not very good" idea behind him was that he wasn't a good character to run back a bad game. Or wasn't thought to be. He doesn't have the same level of dirt as some others, and again, he wasn't particularly showy. But then people started to get better at just playing the game, like a solid, simple, fundamental (as much as anime games ever play that way) style and as they got better at that, and every round wasnt purely about SICKNASTYNOSCOPEDORITOSMIXUPSDAWG, his strengths showed more. Additionally, the fluidity of character swapping in the game helps as well.. Even if he's your 'anchor' if a game isnt going like you want it and you feel like you need a powerhouser like Black or someone to be the last man standing, its easy to make that happen.
Vegeta is a fav of mine due to how he plays. He wasnt originally, but Ive come to like how clean and concise and straight forward he can be. Ive *thought* about swapping Black out and running him instead.. either way it goes Im packing a massively over played character for one of my spots.. but fuck it. I cant make my entire team snowflakes when I like so many of the top characters. Hit isnt rare, but hes not super common and TGohan *IS* rare, lol, so I feel like Ive bought myself a little scumbag room to run someone like Black or Vegeta or something.