with all the hype about the PS4 and Xbox 720, do you think it is going to be possible to finally have a true cross-platform mmo? the speculation on both systems suggest they would have enough power to run TESO.

you think we will ever see the three main platforms on the same server?

Maybe in the future, but not now and not with TES:O.

The only real problem are the input devices. Prefered input devices for PC = keyboard + mouse, PS & Xbox = game pad/controller.
As long as this doesn't change, the answer to you last question remains: "No"

what's got power to do with it?

the real problem is that consoles come without a keyboard and mouse. there's not much fun in an MMO without keyboard and mouse as it is all about communication.

I would hope so for the sake of a larger player base and as long as those platforms dont cause lag.