Honestly the only thing will ruin it for me is if you can't buy houses or have garages... i missed having garages and parking cars in them in san andreas and vice city I will also be bummed if there isn't car customization.
Heres a link thats really similar to this... Apparently a QA tester named OpenSurvivor on the GTAForums posted this and then it got deleted.
http://www.gameranx.com/updates/id/3623/article/rumor-grand-theft-auto-v-info-leaked-by-qa-tester/