Making the level 50 dungeons give EXP is definitely a good step towards making all dungeons/raids and other stuff more relevant. There stil remains more to be done though. Roulettes do a pretty good job of enticing people back to re-run cleared content but a lot of things lack any real incentive or aren't even on roulettes.

It would be nice if there were a lot of good items even glamour stuff that could be made with items from running various dungeons from Sastasha normal all the way through the level 60 dungeons and all the raids.

It could be like 10-20% chance that you get the item after a run if you've already cleared the dungeon before. Collect 5 or however many and you can make a themed weapon/armor glamour related to those dungeons. Like a tonberry line from wander's palace and some others or anything else cool. Make some really cool stuff for the Crystal Tower and people would do it again too. They'd have to look good like glowing, particle effects and stuff.

This kind of thing would mean way more people having fun doing dungeons and less people on the forums complaining about how they can't find anything to do.