To be clear: I think tanks have more than enough incentives as is. You completely missed my point. Which was, if after what's already being currently offered isn't enough to convince people to play tanks, then instead of throwing more trinkets at the players who play these roles they need to look at the real reason 'why' people aren't playing it. Are the classes too difficult/clunky/not involved/etc.
Tanks however, already have enough perks. The basically instant queue alone is enough of a perk to most and that has been a pro to being a tank since basically launch. (ie before any other incentives were offered)
You're calling it a restriction, I'm calling it 'forcing you to queue/play as intended' SE never ever intended for the 'Join Party in Progress' button to only include in progress runs, nor did they plan a dungeon with the idea that you would purposefully queue 2/3 into it. The only reason it is there is because they wanted to allow an abandoned party to be able to replace the member who left...and not punish 3 people for the behavior of 1. But in general, SE expects players to queue for a dungeon and actually do the whole dungeon, beginning to end.
Anyone who thinks that SE planned on any player being able to constantly spam the system to enter before the final boss, get the reward and walk out...is deluding themselves.
-They have been slowly adjusting dungeons to get rid of speed running (and even writing new dungeons so that you can't easily speed run them)
-They fixed bugs that allowed players to use scenery in dungeons to avoid boss moves
But you think the spam the 'withdraw' button is something SE intended and is okay with?
pffft: this does nothing to make greedy players be 'nice'...it makes greedy players even more arrogant and less likely to be nice. When Selfish people get what they want by being selfish ,then all you do is reward their self-serving behavior. When that gets rewarded, then they deem it as 'okay' and acceptable and continue to do it...typically even more aggressively.
Therefore, the only way you get through to selfish people is NOT by giving them what they want, but by taking away the methods they were abusing in the first place. If a 3 year old hits his 2 year old sister so she'll give him the toy she's playing with, you don't let him keep the toy, nor do you give him a better toy/or a duplicate toy. You take the toy away from him, hand it back to his sister and tell him he needs to wait his turn. You don't need to yell at him,hit him, etc. You just tell him he's wrong and don't reward the behavior.
This way, he learns that if he wants the toy he has to be nice, and he has to wait.
That is how you get greedy people to work with others.