Okay, so its not like I’m saying this is the clear cut solution to the game, but I like to think of ideas and share them / discuss them.
But, the main reason I started being a healer main, was to get easier into the groups, whether it being raids, pvp, m+ etc.
Even though I do like the game, some days really tire me out, when I have those classic “healer problems” where people just flame you, I log my dps try to que up or make my own groups, but I’m yet again discouraged by the long wait time inbetween the ques or signups…
And by the luck of nature (or lack of), the second I go to farm a mount in the mean time, wham, que pop, full signup…
So(!) For me, an idea could be some “idle” game mode, that wouldn’t require you to have a group that you could do in the mean time and here are my ideas:
For pvp:
A big PVP zone, made like a “castle” / tower, with two wings that at the top end up as 1 room.
Every floor has different settings, obstacles, pillars, bridges etc. so some rooms will be advantageous for hunters that can kite, some for warriors due to minimal hiding spots.
The objective would be to kill others and be the “King on the hill”. This will accumulate a small portion of conquest points. This shouldn’t be seen as a “short cut” to playing SS or Arena/BGs, but instead of flying around in circles or tab’ing out and watching YouTube while the 40 minute que goes, you can actually get something for playing, small portion, but some nonetheless! And of course, the pvp part!
An alternative could be a “practice” lobby, that you can just que into with bots. either 2v2 or 3v3. But, you are not playing with or against other classes, it will be just shades that move and deal damage to each other, chase each other around, and like a dungeon sometimes they will do a mechanic that CCs you etc. The idea here, is for healers to practice the unpredictable actions that sometime occurs in SS, when a DPS just chases after the enemy behind every pillar, leaving you to dodge 10 CCs on the way. And of course for dps players it would be to stay alive the longest and do as much damage as possible. Whilst also practicing your awareness as you have to keep track of where the healing shade are so you don’t die.
The game is “infinite” until you die (dps) or your shades die (healer). I think this could help people, specially new ones with awareness and reaction to different things, without being met with the “OMG HEAL???” or “You are LoSing me again! useless zugzug warrior!!” etc.
For PVE players it would be a game mode with “waves”, so first maybe 1 mob, then 3, then a boss, something like the Brawlers Guild, that can help you practice your rotation, utility use etc. without it having to be against a target dummy that doesn’t require you to move out of stuff etc.
For healers, it would be to keep NPCs alive like the healing mage tower challenges…
This would be like Mortal Combat, where you move up further and further and can win rewards for each floor you clear. Could be crests, tokens for tmog, gold, etc.
Again, this is not a revolutionary game mode that needs to take the place of something existing, its just a gimmick idea, that could help maybe some people pass the time inbetween ques, maybe even help some improve the gameplay with simulations.
And before people mention lower keys, HC dungeons, normal dungeons, arena skirmish and random BGs… Even those game modes are flooded with veteran players that just want to do it as fast as people and from time to time will either kick a player or just leave them behind while they mass pull leaving no “real” experience.
Sorry for the long post!
What do you guys do inbetween ques? Maybe I can get some inspiration from that 
