I agree - I'd rather see the extra CPU used for things like being able to route mono signals more freely and easily without needing to make panning blocks and doing weird splits. Similarly, being able to use all digital I/O at the same time rather than being limited to only one type.
There's also things like running 2 presets at once (say you had 2 guitarists or guitar and bass with their own chains, and they could each switch internally on one global preset). Or perhaps (as Nathan said) combining several blocks into a single "macro" block for the use. And a big one would be to finally consolidate amp channels and modes into single amp models because IMO that really does make things feel a bit dated compared to having an all in one model.
As much as I love modelling accuracy kicking on and getting better, it would be a shame if thats the only area that gets any attention with more CPU available. I highly doubt that'll be the case, although I'm sure there are likely a few ideas Cliff has that need the extra grunt.