There a handful of missions that are decently interesting, with a couple of cool moments, but they do occur well past the halfway point of the game. Additionally, there are some moments in which the environments or at least the atmosphere come across like a true revolution should. It is during these that the glimpses of what this game could have been really do come out, however once again, these are very few and far between.
This game is really trying to be something more than it is, and you can tell that there were some heavy problems during development, especially with it switching hands the few times that it did. This can absolutely needed another delay IMO, but I think they realized that they just needed to get the game out now and not invest anymore time and money into it, as there is already very little hype. The development team certainly could do much more, and I wish them all luck, but it just seems like a case of bad circumstances leading into the development of this game.
It isn't really a collect-a-thon as much as it is trying to be similar to Far Cry and Dying Light. There are different regions, and within those regions, there are small activities that you can do besides the main missions. However, these ultimately boil down to turning on radios, and cutting the power to KPA equipment (however this is as easy as pressing square on them, with half of them literally just sitting in the middle of the street). There are some other minor things besides those two, but they ultimately feel very unrewarding and often times unnecessary.