For every fun explosion, there's so much annoyance in this game. I'm really disappointed.
Locking essential mechanics behind (mostly) tedious minigames with minutes of loading is just baffling. Locking vehicles behind stealing them and driving to a garage for every single car there is (after first unlocking the possibility to drive higher-class vehicles to the garage), is one of the most unfun things i ever was asked to do in a game. Why not give me some unlocks with chaos points? Why do i even collect them, what's the point of this metric now?
Pop-in can be atrocious. I just landed my helicopter on a mission-start marker, i was there for about 4 seconds, wanted to exit and was wondering where the hell is the marker on the ground? BOOM, the marker together with several small buildings, fences etc. pop into my landed helicopter while exiting, destroying it and me from it's explosion. The hell...?
The physics are sometimes all over the place. Ricos ragdoll is especially over annoying, flailing around from every little bit in a game that's about explosions. Coupled with the abundance of shooting enemies in bases and your little health, liberating bases is more often frustrating than fun for me.
There are many little things, where i don't understand why they've been changed. I want to zap quickly to a parked helicopter, now that there's no stunt option, Rico's always standing on the cockpit window, between the rotors, you name it. I have to walk down, around, and search for the "Enter" prompt at the cockpit door. This was waaay better in JC2.
Cave bases seem awesome at first glance, but they limit your traversal options quite heavy. Again, coupled with hundreds of people shooting at you, cannon boats firing at you, there is more frustration than fun for me.
Explosions are fun, yes. But i'm at a point where i've seen every of the 20+ things, that can explode, destroyed several times and it's getting quite boring.
Framerate and loading times (especially loading, how could something like this ever get released?) were already mentioned by others.
I'm trading it back in, JC2 was way better. Aside from some design decisions regarding unlocks, the technical shortcomings, i have a feeling Just Cause is just not anything interesting anymore in this day of open-world games, at least for me personally. When it's not frustrating, it's get boring really quick. A shame, i was really hyped for the game.