I would tolerate this a little were it a FPS combat sim but not if there are lot of unpredictable RPG factors that would get me killed or slow me down. A turn based tactical shooter seems more ideal for simulating combat stress and can have RPG stats. Otherwise it feels too much like an arbitray restriction on a player because they happen to be in a paniced situation. In several FPS games they already do emulate such effects with blurred vision, ringing sounds, and inaccuracy under fire but not to the point where the player feels out of control with the character.
Will the player feel more paniced and connected to the character in that way? Or will it cause players to behave differently to avoid the penalities? (keep from getting under too much suppressing fire, don't stand near or look at the characters that die, etc)