The entire set of 50 dungeons I've really enjoyed. It's the fact that there are a lot of trash, that makes people gather everything up. Then it turns into one huge AoE battle of dodging and doing attacks. Melee DPS either just eating the AoE or having to stop, dodge and go back.
Take WP, there shouldn't be so many groups of 3. That's just encouraging people to gather stuff already and AoE it down. Instead remove a set and place in a larger Tonberry to fight. One that buffs others who are near it somehow. This would stop the massive gathering, but in return the removal of so many sets of adds between bosses. From the start to the first boss. I think if you had the first set of 3 one being a smaller , then a large Tonberry who had a job say being a Bard, singing songs and buffing. Then at the gate have just two smaller Tonberries who drop the items needed.
Like Dusk Vigil, I enjoy that one. You have your sets of 3, but one is a bomb that can be annoying. Then you have your larger mob, then another set of 3. The frost debuff is nice too. The Vault is by far my favorite, even though there's a large gathering of mobs, they're rather weak. Still, when you see the BLM one you know you need to take him down because he's going to be annoying. DPS get to him fast. In situations like that I would have the BLM give aoe Aether Spikes so all who damage him / anyone near him gets hurt..
Lol but I think of really cruel things..I'd add bees back in the wall! I would love Primal dungeons. Like running through an inferno based dungeon just to find Ifrit EX waiting.
Those were fun, you had to get a party to go in and get relic. Or when you walked in and you saw all the NPC's fighting each other but didn't know what to do.
Every dungeon though really is beautiful and interesting in its own way, just after running it so many times you get worn out. Then you take a nice long break, suddenly you don't mind returning to AV.