Funky Papa
FUNK-Y-PPA-4
There are many interpretations of what elements make a Doom game... I don't think cartoony color is it.
You can only do so much with Photoshop. The thing is, Doom always had a high contrast look, while the new game is largely monochromatic. That shouldn't be the case.
I'm sure modders will go to town. I personally cannot wait for the remake of the some of the most classic WADs.
As for the alternative fire modes, I'm somewhat conflicted. Doom could use some changes there (Blood is a brilliant example of a similar kind of FPS that used alt fire modes to great effect), but too many of them could detract from the game's simplicity.