Yeah it has, but not so drastically you won't recognize anything The visuals have had a serious upgrading, better back grounds, better characters, better beam-sprites, and more diversity as well, and the controls have been altered for the best. Instead of having to hold an attack button to block, and in that way prolly get hit by blocking too late, the blocking has it's own button.
I'll list what every button does:
A: Ki-blast(+R= upgraded Ki-Blast,+X=attacks such as Kamehameha)
B: Guard(+Y=Throw,+B=Super Guard, stops every attack)
X: Strong punch/kick(+A=attacks such as Kamehameha)
Y: Weak punch/kick(+B=Throw)
L: Teleport(only Goku),Transform character(Normal Saiyan>Super Saiyan)
R: Charge Ki(+B=Super Guard, stops EVERY attack)
D-Pad: Moving character around, dashing(+R=Quick Flight, move to opponent character very fast)
Touch Screen: Activate Team Attack, switch character by touching their portrait.
It's all very natural whilst playing, even using the touch screen for the character switching.
The Team Attacks are also a new element. Certain characters combined in a team can do a special move together by pressing the "TEAM" icon on the touch screen, and they look mighty fine, if I do say so myself. Another new element is the Ultimate Attack, which you can use when your Health Bar(now fully upgraded INCLUDING a character portrait) is in the RED. It is a devastating attack and, ofcourse, differs for each character. Normal Goku will use his Kaio-Ken, but Majin Vegeta for example will do his Final Explosion, also used on Buu in the series. If anyone has any other questions, even about unlockable characters, feel free to ask...