There's two ways I see them going with this, and I think both could potentially be very badass.
The game is played from First Person perspective and the combat is all in real time (ala Morrowind). I know it wouldn't be traditional Fallout, but I think it could still be pretty sweet. With some Karma physics integrated we could have mutants exploding and body parts tumbling around in realistic ways. Different, but good.
Turn-based, isometric view, strategic battles--classic Fallout style. And if they updated it to be like Silent Storm (destructible terrain, ragdoll physics, etc)...*drool*
So basically either way, *fap*fap*fap*fap*fap*fap*fap*fap*fap*fap* !!!