Nades are hard, definitely, but I don't think they're the worst. In fact, once you have seige, they're kinda fun.
And hard to get? Yeah, but a challenging quest is a good thing, and there are so few now in the game.
Pistol, on the other hand, is just as boring to level (no combos, no fun graphics, just point & click... repeatedly), and really has no usefulness once its mastered. That one I master first, and then pretend it doesn't exist.