Yes the plasma rifle was the match to the AR, but it did not fully match the AR and the Suppressor. The Plasma repeater from Reach more similar to the AR, and now they pretty much made a direct covie version of the AR. Nothing wrong with that. Yes the storm rifle overheats, but that is a downside to all covie weapons that do more to shields than health. Each weapon type (Human, Covie, Prom) has a strength and weakness. The covie overheat but do more to shields, human fire fast and burn through ammo but do more blunt damage (health), and prom weapons are a mix of the two. 343i is trying to make a weapon to fit each of the three...they fel that the plasma rifle didnt cut it so they replaced it, we wont know if it was a good call until the game launches, but it appears that the storm rifle is a good replacement.