"Ok it is cuz thats how the SHOW IS."
Um.. All I'll say is Krillin. Krillin wouldn't be affecting people. lol
Vegeta is and isn't the strongest character. It depends on how you want to play. In the long run, he might be, but.. I don't know. In a 30 minute server I doubt you'll reach SSJ, if for very long if you do. He's balanced with Goku, I'd say. Goku transforms earlier, but when Vegeta does, the Final Flash can beat a Kame. The tradeoff is is that the Flash will run out of ki a LOT faster, so you'll have to be close enough to probably blow both of you up if they're fully powered. The Big Bang is really the only advantageous thing Vegeta gets from transforming, I'd say.
I use Gohan normally and never transform, and then Goku when I'm pissed off or if I feel like really playing. I rarely transform, so.. *shrug* There is no best character, to me. But there's certainly the worst.