This idea would be worthless unless they increased the rewards given based on what alliance raid you got. As it is, in my opinion, alliance raids aren't worth doing in the first place right now, but that's besides the point. A 30 minute penalty isn't actually that bad when you would be potentially spending well over that in an alliance raid, that is prone to wipes - not because they necessarily cannot do it, but because others cannot do the mechanics or play their class to a sufficient level. However, in turn if the rewards are increased too substantially then you may get an issue where people won't ever want to do the old raids anymore either. Similar to MSQ roulette.