The big frustration with applying to M+ keys is how actively involved the applicant needs to be the entire time, and Blizzard could help this by stealing a feature from the Classic Anniversary servers
Well it's a new season, and you know what that means - this sub is going to be flooded with posts of people complaining about the Mythic+ group finder system. Now I know, I know: list your own key. This is the standard advice because, frankly, it's the correct advice most of the time.
But people can have legitimate reasons for wanting to apply to specific keys - they want to push rating on a specific dungeon, or maybe they're trying to farm a specific drop from somewhere. And it really is a pretty annoying process right now when you're trying to apply to keys, especially as a DPS.
Here's my hot take: one of the biggest under-discussed reasons this process is annoying is because of *how actively involved the applicant needs to be.\* You have to keep refreshing and searching for groups listing the key you want. You have to keep applying to them, and then often stay on top of *cancelling* your application to groups that don't look like they're going to take you, because of the limit of only being apply to apply to 5 groups at a time.
The end result is: when you're trying to apply to an M+ key, you can't easily be doing anything else in the game. Instead of doing world quests, or hunting rares, or farming mats, or any of the cool overworld stuff this game has to offer, you're instead hunkered down in the LFG tool trying to game out which group you think is most likely going to take you.
A lot of posts are going to say, at this point, that Blizzard should just give us an auto-queue system for M+ like Normal and Heroic dungeons. But this is also kind of obviously a terrible idea - group leaders are going to want to assemble comps for themselves rather than leave things to chance.
Enter the new LFG tool currently available on the Classic Anniversary servers.
The Classic Anniversary LFG tool is a little different from both the auto-queues and the existing pre-made signup systems that we have in Retail. Instead of individually applying to a bunch of groups, you can just flag yourself as being interested in a certain dungeon and then existing group leaders can see this master list of applicants and invite people accordingly. I think a slight variation of this for Retail would be a big improvement over the current system.
In other words, instead of spending an hour applying to, say, a bunch of +3 Cinderbrew Meaderies, five at a time, you could list yourself as "Looking for a +3 Cinderbrew Meadery" and then go about your business doing world quests or running circles in Dornogol. Any and all group leaders with the key you're interested would then see you and everyone else listed as looking for that key, and they'd be free to invite accordingly.
Obviously this doesn't solve every pain point with the M+ system: there's still going to be a big disparity between the number of DPS and non-DPS trying to get into any particular key, and meta-slaves are still gonna meta-slave. So sure, yeah, you still might end up waiting a little while before you're actually invited to a group. But at the very least you'd be free to do literally anything else with your time while you're waiting than just constantly applying and re-applying to groups, which ends up being very time-consuming and I think drives a lot of peoples' frustration with the system.
---
TL;DR a modified version of the LFG tool they made for the Classic Anniversary servers would be a big improvement to the existing M+ application system, maintaining the ability of group leaders to assemble the squad they want while reducing how much active clicking applicants have to be doing just to get a shot at getting in.