I cannot disincentivize the game for what it does well. The game is a high flying shooter with excellent build components and satisfying combat.
If that's okay by you, this game delivers.
They did away with most of the racing elements, making it more optional. The first race, though was mandatory. If you are like me, you will grit your teeth through it and never touch it again.
Most of the characters in this game are more over the top than they were in the first. When you create such bombastic personalities, one detaches from association with them and the story and motive to play the story suffers. Even Borderlands didn't go this far.
The villain was simply a sadistic jerk who wanted to recreate the species - though the reason why was never quantified. In reaction to Rage 1's "Why should I hate the Authority!?", Rage 2 went all the way the other side and created a stick figure rather than a being with a logical train of thought.
ID games has never been big on story and their games have all suffered for it. I would rather no story than the stuff they continuously deliver. Would I start the game as a marine with a pistol and fill in the blanks or Satan's nightmare (and where do you go from there!?!?). The thing is, without believable story content in any game, you might as well be playing tiddlywinks in a sandbox.