I guess people saw it and went "hurr goobysoft collect-a-thon"
I didn't see it and think that...but that's definitely what it turns into late in the game. I enjoyed it, actually got the platinum trophy collecting all the things, but honestly it stretched on a little too long (even though that's something we aren't supposed to admit to game developers these days).
There wasn't enough gameplay variety at the end to make continuing the exploration interesting, even with all the skills unlocked. The main story missions were decent and worth finishing. I never played any of the DLC.
Narco road is OK, fallen ghosts is the best content in the game ---