Its easy if you can cope with several different things to keep track of, and impossible if you can't. This gap cannot be bridged by effort either, because it's a hard limit in many peoples innate ability to concentrate.
The old style of wow as an RPG on all levels was "simple to perform two or three mechanic stuff, if you get beat go farm DPS/resist/tank/etc gear and come back with more numbers" the new style is an ever increasing blitzkrieg of shit to remember that gearing or HP nerfs to bosses makes feck all difference to. For most players, it's not working.
Edit - and to keep it in line with the OP, openraid will get worse as more people join it because wow just isn't designed wuith the average person in mind and the more average people who join up the worse the experience will become.