If they are smart no. The big thing GTA needs right now is density in their cities. For all the look and vibe their cities have they might as well be card board cut outs because you can't really go in to many buildings or do many things.
GTA needs to tackle its games like skyrim. It needs to feel like all the quests are happening organically right in front of you. To do this they really need a smaller space to work with.
Best thing for them is make a smaller section, and offer other sections as DLC with their own story lines integrated later on.
If they are stupid then yes they will offer just as much content as san andreas and none of it will make much of an impact post skyrim.