Here is a very controversial idea that imo would make tank/healer gameplay more interesting:
Make dungeons require only 1 of tank/healer, not tank + healer. Option for standard comp should still exist ofc.
Healers can solo many dungeon pulls and bosses, same with tanks. To the point that some skills feel like overkill.
So why gatekeep dungeons behind strict rules when dps queues are multiple times bigger than tank/heal queues?
While some things like tankbusters might have to be tweaked for this, it would allow for more niche skills like CC and self defensives to be useful. Crazy thing to say, CC skills being niche lmao