Wonder if they'll stick with the trend they had with 4, or revert back? They did get themselves a lot of complaints about some of the "boring" aspects in 4 (Bowling, for instance), but at the same time I'm not sure they've got the experience of wacky unrealism to match with Saint's Row. They did seem to dial back the grittiness in the DLC (esp. Ballad), so we'll have to see.
I'm interested either way. Of course, I would love GTA5 to be set in a London-expy, but that's because GTA: London was awesome.