Hmm..Right now the closest thing to a DBZ Online game is Dragon Ball Source, a CS:Source mod. which looked pretty impressive.

As for this game, it'll probably do well amongst hardcore DBZ fans but with some many other MMORPGs to compete against I doubt it will be the next WoW or even come close. And with features like marriage etc. it seems aimed more at casual gamers.

It would be great if they made a new Dragonball Z game with online play. A story mode and a pure fight mode winner take all.
Not only that, but a crossover server that would allow Wii players, and 360 players to fight with each other too. Break the barriers I say.

Well that would require some sort of partnership with Nintendo & Microsoft. Plus, if it took Microsoft a while to pull off PC vs. Xbox 360 multiplayer it would take even longer to link up WFC with Xbox Live.

And there'd be various problems such as no mic, gamer tags etc. for Wii players.

So the possibility of this happening is slim to none. PS3 Vs. 360 multiplayer could probably work though. It would be good for cross platform games like CoD 4 etc.

Well I have some plans to submit ideas to Nintendo and M$.
It is possible, believe me.