I'm several hours into FC6, and there isn't much that's surprising me so far. It is a very typical Far Cry experience. I've seen others complain about the weapons and progression... and I'm not seeing a problem. You get weak weapons early in the game, you can improve them as you go along... shocking. You get better ones later, and you can improve them too. It isn't a "radically different" system than you get in a lot of games. I haven't had any problems yet... then again I'm not a speedrunner rushing into high security and late game areas with my starting weapons and crying about headshots not being instakills either. As long as you follow along and actually play at a measured pace, the balance is fine. The easiest way to deal with the "different resistances and bullet types" that people are complaining about... JUST GET THE ARMOR PIERCING ONES. Soft bullets are better against unarmored opponents... but the armor piercing ones are still plenty effective. You can get fire, poison, or explosive rounds... and there's no reason to bother. As long as you have some kind of explosives or launcher to deal with vehicles, all you ever need is to outfit guns with the armor piercing ones, and you can deal with anything.
The most surprising thing, they are not obtrusive with the microtransactions and nothing in the game has tempted me to bother with them. I really haven't seen a lot to complain about, but there isn't anything that stands out as particularly good either. Just more mindless shooting and really, that's all I expect or want out of a Far Cry game anyway. I even like the "perks" being tied to equipment change. In previous FC games you just become OP and able to do everything and the game loses all challenge pretty early on. At least in 6 you have to make a plan, outfit accordingly, and can still mess up and have to leg it if things go wrong.