He's right, that's a terrible idea: so terrible, we couldn't leave it alone.
Whenever a celebrity dies, people express their grief in different ways; some of it is tasteful, but other times it's just tacky. This set-up, as suggested by Will West, would definitely fall into the second category. Horribly, horribly misguided. But also funny, when it's done on purpose - and if there's one thing Robin Williams was known for, it wasn't shying away from inappropriate humor. The "bad choice" he's referring to is this tribute art: even now, he's picking on our poor taste.
Since we din't have any of the Mork toys, Genie had to fill in for Robin Williams. Macho Man and Egon are portraying themselves.
And lest you think this is totally tasteless and just as low as it could possibly be, we considered making his line be "and I thought agreeing to Mrs. Doubtfire 2 was career suicide!" At that point, even we would have been horrified.
Other movies we considered name-dropping were Bicentennial Man, Death to Smoochy and Old Dogs, but of all his many terrible projects, RV fit the word balloon best.