Well, I may consider doing that when the new ESF comes out!! And, I already added an SSJ4 Vegeta!!! I am also trying to get my hands on an SSJ3 Goku, which is in my opinion, the best character/transformation from DBZ!!!
I think they should continue the series and change ss4 to something else, liek ss3 while sparking like the ss - ss2 change. that wuold have been a lot better, ss3 is k00, but DBZ gets kinda rediculous after ss2 and even during ss sometimes. the ss4 form kinda reminds me of the time kakarot went ss in "Lord Slug"