I've voiced lots of promos and have seen similar campaigns before. It's a valid way to approach this transition.
The thinking might be something like this: There's no need to do the usual... toot the horn about games, prizes, excitement, etc.... because everyone knows the show. Therefore you only want to focus on Drew, that's the message, and you only have a few seconds in those spots we've seen. So do you show Drew smiling, handling a Plinko chip or something similar? The glasses and graphics are obviously memorable and the lack of audio from the show or traditional voice-over actually breaks through the clutter and attracts attention. A common theory among promo producers is that sometimes by showing less you have done more to build anticipation.
I think it worked well, and don't have any reason to believe it was done in deference to Bob. I think those days are over.
But what do I know... I just yell "come on down" for a living.
Randy
tvrandywest.com