My guess is that VST plugins will not work because of a different processor achitecture. My guess is also that Steinberg is not interested about the mobile platform (at least not in the near future), so do you think a mobile plugin standard will emerge from somewhere else?
I mean there is Nanostudio, now FL Studio mobile, and I am pretty certain that there is a mobile version of Ableton Live in the works too.
Or do the companies trust that no plugin format is needed because musicians would anyway do the real work in a workstation and use tablet/phone only for scetching?