To be fair, I doubt GTAV will be as bad as GTAIV.
Rockstar has learned a lot since IV, in their writing and gameplay. What with Chinatown Wars, Lost and the Damned, Red Dead Redemption, and more. They've especially learned a lot about their engine RAGE.
I think there's reason to be excited, but it could just as easily be a disappointment. I'm waiting for the GI preview before I have an opinion, but I just wanna say that art is absolutely delicious.