I fully agree with the game feeling fantastic to play and control, in addition to it sounding and looking great as well. I also didn't mind the more open nature of the missions, the loading times while in the helicopter, the base building (payment) shenanigans, or even the overall absence of a (more satisfying) narrative conclusion.
However, the one thing that really makes me not want to return to it, and it pains me to say this because of how much I love the gameplay, is that I now know in hindsight that Afghanistan and Africa are the only two areas you end up going to.
I played the whole game thinking that we would be visiting 4 or 5 distinct geographical zones in fact, in part because of the focus on dealing with languages, collecting animals and such, and when considering the mobility and reach of the Diamond Dogs as an army. I also thought that travelling around more frequently would be tantamount for the devs to keep things fresh (which imo it is). Imagine my disappointment and surprise when I found out that Africa was the last zone we'd go to! I actually expected something like a snow/tundra area as well, or something more urban, or a tropical zone, or even the promised return to Cuba; in short anything beyond having just the two we did get.
I feel that this point of criticism is not often being brought up compared to stuff like the incomplete story, the missing final chapter, the repeated missions, Konami's greedy pay-to-win practices for the base building meta-game, Quiet's objectifying outfit etc, but to me these are far more easy to ignore due to the sheer quality of the gameplay. The lack of environments, however, is not something I can ignore as it seems like such a wasted opportunity to not be able to apply all that gear and tactical gameplay in more zones while dealing with other languages, terrain and environmental hazzards. A real shame in other words, mostly because of how great the game plays.
Sorry for the rant - apparently I still had to get this off my chest. Hopefully it's relevant because of how it ties in directly with the actual strengths of the game and its fantastic gameplay.