I'd draw a distinction between talent acquisitions to go join the general pool of people at a big company, and talent acquisitions to work on the big new focus of a "sleeping giant", in something similar to what you were doing before.
Wasn't Etherpad the latter, and then they found out that big new focus had been canceled and quit? Same with Dodgeball, Aardvark, Jaiku, Jotspot, and any number of other acquisitions.
You shouldn't assume anything about what your job duties will be in a big company, even if it's written into your contract. Big companies have an internal logic that often makes no sense to the outside world, and usually depends upon what the decision makers are paying attention to at the moment. Priorities change.
Other than YouTube and Android, nothing Google has set out to do approaches how seriously they are taking Google+. Bigger than gmail, definitely (which, for acq, is tied to o Grand Central I think)
Wave had its own issues, mainly due to being political and inviolate, from what has been written outside google. It was really sad to see etherpad get caught up in that.
