It's an RPG. It has some shooter mechanics, but like most other RPGs your effectiveness with weapons boils down to your stats. Each weapon also becomes more effective if you give it a moment to focus a critical hit (this is especially important when making stealth kills with a pistol).
The bad reviews this game got really are a shame. Could the shooting and stealth mechanics have used some polish? Yeah, they could have, but still, it's an RPG. Those mechanics are not supposed to be dependent on the player's control skill. The rest of the game was great. The plot was a good spy thriller that basically allowed you to play with the attitude of Bond, Bourne, or Bauer. The characters were pretty good ("We are now approaching the station. All passengers prepare for boarding. In other words Mike, DUCK! *cue Steven Heck passing by on a subway train with a minigun and wiping out all the enemies*) and the plot's flexibility and player control surpasses virtually anything BioWare has ever done. I'd give it a 8/10, higher if it was more polished.