Don't plasma screens operate awfully hot? One of the nice things about LED's is they run cooler, with LCD's somewhere between LED and plasma.
As to resolution, there's definitely a point where the benefits are outweighed by the need to calculate for more pixels. I fly X-Plane in a full size cockpit using a 42" HDTV, but only use the 1600 x 900 resolution. Frame rates are much better, and the outside view at altitude is very acceptable.