It's doubtful GSP has regressed to the point he can't stuff & jab Maia to a UD, but Woodley's TDD and striking are trouble. Neither is a big fight to come back to, not a given he'd return to do the same old, same old.
Like what does beating Maia or Woodley do for GSP's legacy? Would be a bigger deal if people started to consider Tyron as the WW GOAT, he'd have something to prove. Probably still wants to get Bisping.