More powerfull then what?
Owning an n-gage myself I have to say I am pretty pleased with it. Only not because of it's games but more for it's all in one package. In travel a lot by train and bus and in one small gadget I get a games machine, radio, mp3player, phone, email, wap, internet, agenda and a lot more. Most of the games I play however are series 60 games. So you could just buy any series 60 phone for games. The ngage games themself don't amout to much (in my opinion) with Tony Hawk being the best.
As for arena although it's sounds fun for now it isn't. You can only do shadow pley at the moment. Meaning you can download someones fastest run and compete against it. There is no online multiplayer at the moment.
So in conclusion I really like the n-gage, but not as a games machine.