Tekken 6 will definitely please many veteran gamers, despite the small changes in gameplay. The customisable characters will provide you with plenty of offline experience. However, with games such as SoulCalibur IV that have massive in-depth character creation/customisation modes, Tekken is starting to lose momentum.
The roster may be huge, the gameplay still by far the best (bar the juggling), but the fact that there are long load times and a dry online multiplayer experience, Tekken 6 could have been a lot better than it actually is. Nonetheless, this is still worthy of purchase if you love fighting games, since it will definitely prove to be a major challenge.