I agree with the OP, but it probably wont solve one of the major problems I have with the end-level roulette mentality; people assuming you also have done the dungeon enough times to do it blindfolded.

Me and my friend queued up for a 50 dungeon that neither of us have done (both of us dps). And although the chat-log clearly informed the party that at least one person is doing this for the first time, tank and healer blazed off, pulled 5 groups, and we had to catch on to the plan and aoe things down. Once we reached bosses, we fought them. No explanation was given, and no time was given to ask, "Hey, is there anything we need to know about this fight?". Only getting yelled at when we did some thing wrong (that isn't obvious unless you knew the fight).

After completing the dungeon and reflecting back on the run, it didn't feel like me and my friend did a dungeon. It felt like we were two lead weights that were inadvertently being flailed about as the tank and healer were sprinting to the finish-line. Even though we completed the dungeon successfully, it certainly wasn't enjoyable.