Meh, I completely understand the appeal, and I do have high respect to the level of craftsmanship to Rockstar for the series, giving the freedom to do the increasingly widerange of fun actions in such an open world.
But for me, I'm actually going to wait a little bit and see some more reviews regarding the game, I've always had more of an interest in having a more specific mechanic that's not just "Everything is possible." Oh, yes, I totally think that's an amazing prospect and what makes the series so strong, but my personal gaming picks are with a more-centralized, more-effective theme.
Like that one "Watch Dogs" game coming out in a few months, an incredibly open world but with a specific theme of being an expert hacker that can control pretty much the whole technical array of the city... That's what I'm going full speed into.
Just my wandering nit-pic's. Go have your fun in this ridiculously open gameplay... Who knows, maybe I'll change my mind after hearing some other people's endless praise for it.