That is something that already happens for "Duty Complete" parties. Someone who is clear ready might struggle to find a clear group that can actually clear a fight. So they message party leaders for reclear parties explaining their situation and asking to be let in.
Another potential workaround that I could see taking off is people using the normal tabs to recruit for high-end content. For example, someone who wants to run M4S could make an M4N party on Aether and write in the description that the group is for M4S. If a few people started doing this then it wouldn't take long for others to notice and make it the norm. One issue with this might be someone seeing an M4N party and joining it without reading the description but using party finder for current normal content is unusual when they could simply queue for it. ilevel requirements could also be set to require some savage gear and make this less likely. Another issue would be the inability to use duty completion settings to filter players who haven't cleared out of your clear group but rather than discourage people from dc traveling to raid, party leaders would probably check logs more often resulting in some toxicity as players who have cleared but lack any logs are unfairly kicked.
Right now, on a Sunday afternoon, I only see 4 PF listings on the high-end tab for Crystal and when I was on Aether an hour ago there were 40-50 listings. A strategy that more people are using to play on Aether is to wait until very late at night to transfer over and then park your character there until you feel like playing. I strongly believe that if someone thinks their raid experience will be improved on another server they will do whatever they can to get on that server, even if it means losing sleep or talking to people.
There does seem to be many anxious players in the playerbase but I think people who are so anxious they can't even speak with someone are less willing to do high-end content in the first place.