I think MGSV would have been even more fun without the fulton. If you actually had to drive a jeep into a transport helicopter you'd call, if you actually had to free prisoners and help them get out to a transport, that kind of stuff, it would have been better. Imagine all the things that can happen if you actually need to help those prisoners get weapons, as you sneak out of the cells you take a guard down, one of the prisoners gets a weapon, and so on. Once you're outside, since you got to get to a chopper way out of this location to avoid it being spotted and shot down, you and your buddies now need to hijack a transport, maybe one will drive a truck, disguised as a soldier, while everyone else hides in the truck.
That's just one of so many possibilities. You could rescue someone on your horse, get chased with him shooting at the pursuers while you control the horse. You could bring D-Walker to forcefully make your way into an area to help people escape, etc.
You'd be stealing or recruiting people less often, but it would really complement the open world nature of the game much better.