If it's an RPG, it's an RPG; if it's a shooter, I generally want it to remain a shooter. The first FPS I recall using RPG elements was No One Lives Forever 2, where upgrading your skills basically made it so that you did things faster. By the time you had your weapons skills fully leveled up, the main difference was that reloading only took one second, effectively removing ammo management as a game mechanic. Improving my skills shouldn't mean removing elements of the game.
That said, I'm certainly not going to refuse to play a game because it has RPG elements. Maybe the great shooter that puts these elements to good use is still out there, and I'm just yet to give it a shot.