Ideal outcome: Samsung keeps producing awesome handsets, but uses stock Android instead of Touchwiz.
They won't. It will be very hard to differentiate themselves from thousands of other Android devices.
So yeah, I don't buy that argument. Sure they'd prefer if they'd do their own thing, but I'm sure they wouldn't be too mad about if it if all they could use was stock Android (which by the way, they seem to be using in their Galaxy Camera).
If Google is the only one making a cross-license with Apple, then that scenario is even more likely, because the deal would obviously cover only Google's own software implementations, and not Samsung's or anybody else's. So then if a company wants legal protection against Apple, they'd have no choice but to use stock Android. Win for them, win for us. If some decide to keep on making their own custom software, then the legal risk is all on them.