My guess would be that they could, but won't. The GSII could handle a lot of it, I'm sure — but to me, this is like Siri available on the iPhone 4S and removed from the iPhone 4. The GSIII isn't revolutionary when compared to a still-decent handset like the GSII, so a lot of the selling points will be in software capability. Whatever iteration of TouchWiz we get with ICS for this series will probably be all that's coming.
Then again, anyone's guess is as good as mine. Except Joe. He can't guess his way out of a paper bag.