I'm about 7 missions in, and while the game is obviously fantastic from a gameplay pov, I can't help feeling like this is going to be this gens MGS4, meaning the fanbase's opinion on the game will likely shift after the hype dies down. As mentioned before, the "open world" being empty and kind of a drag to navigate is a huge issue, and it's definitely more PW than classic MGS. The lack of story or real context for your missions also makes the entire game feel completely disjointed, which is also not helped by the weird choice to constantly have credits rolling.
Still, I'm having a damn good time playing. I'm just glad I came to terms with the fact that classic MGS died after 4, since I probably would have been really disappointed if I was expecting that from MGSV like I know some people were.