Now I haven't been keeping up with the vids or interviews but these points seem to point towards GT kid Goku only being a costume:
1. SSj1 and SSj3 GT Goku have not been shown (and if GT Goku is a costume, then they wouldn't be in the game as DB Goku can't transform).
2. Adult Z Goku has SSj4.
Now I guess there is also 1 thing that seems to go against this:
1. DB Kid Goku has not officially been confirmed and if GT Goku is just an alt, then DB Goku's main costume would of been more likely to be shown first.
Now then there is still a possibilty that DB Kid Goku has been confirmed through his alt costume of GT Kid Goku and just hasn't had his main costume revealed yet. But to someone who has been keeping up with this game, please give me some facts or evidence from either interviews or pic/vids that GT Goku is in fact a real character. I hope I am wrong...
Also on a similar not , how do we know that GT Vegeta isn't just an alt costume of GT Vegeta.
in the cardass games, GT Kid Goku did have SSJ3. But i fink there just being lazy and not giving him SSJ4 so it means less coding. I mean, how difficult is it just to make Kid Goku transform into Adult Goku? it would be the same as frezia transforming from form 1 to form 2
GT goku HAS to be a seperate character. i wouldnt make sense that db goku was in B3 and they all of a sudden take him out...they just got lazy and said "eff it! leave ssj4 as a transformation for Z goku, they wont give a crap" : (