I like this game very much and I still enjoy it from time to time when I play with friends. We take full advantage of our imagination and what there is to do but it seems to me that Rockstar overlooked the importance of interaction and real-time activities in an open world such as GTAO.
Activities that you can do "on the go" without always having to launch a lobby session or mini-game - most of which are time limited.
An example would be being able to grab a surfboard and hit the waves for no other reason than to have fun.
Or just the simple action of being able to pick stuff up and hold it or throw it at others. Another good example of "on the go" stuff would be the ability to climb mountain walls and some buildings.
Scuba gear? Hunting? Fishing? Casino? These are just a few things, I'm sure you can think of a lot more. Character models and movement is limited and there's no crouching ability unless behind cover.
If you find yourself driving, flying, running, parachuting around most of the time it's because that's basically what you are limited to.
Stunts are fun and with the creator mode I'm sure you can create your own stunts. But when you play your own creations you are limited by time and no longer in free-roam.
You can interact with the police but we all know how that ends. Pedestrians are fun when they decide to fight back or when the guy says - "What the f*ck duuuuude?!", and you just have to kill the bastard.
But you can't ask them to jump in the car with you and drive them off a cliff.