I really think this is the ONE WAY Grand Theft Auto could learn from Saints Row (specifically, part two). GTA has some cool missions, but often, they lack one key thing: Fun. What about more versatile missions? They did a lot better with this in The Ballad of Gay Tony expansion pack (the golf ball mission that opens that DLC is some of the most fun I had with the entire series), but not all the missions have to be “cool.” How about some “silly” missions? How about some “anarchy” missions? How about some missions that may take place in the subconscious of the main character, like the dream sequence from Metal Gear Solid 3?
Between you and me, the way I thought this would play out would be that the series would eventually jump to the future, or take place in space. I know that may sound silly, but right around GTA IV I thought the series needed a reboot, and perhaps a place like the future or some distant planet would be perfect for rewriting the mission structure. Think about it, jacking mechs and shit like that? It never actually happened, and the Saints Row series seemed to be the one that went more in the sci-fi direction (even though it has existed for a decade less than the GTA series).
So I am hoping, even though this GTA seems to be taking place in the same universe as all the others, that the inclusion of the three characters you can switch between will also, hopefully, switch up some of the mission structure they seem to adhere to when making these games. Follow, race, chase, and kill gets old quick.