Yes the problem with SE is they make you repeat boring tasks you don't really want to because you have to do it to progress. Fortunately, it's no longer as bad to cap myth as it was in 2.0. You can do bahamuts coil for 200, crystal tower to hit 250, and a couple daily dungeons and you're done. Heck I farm ifrit extreme to hit my cap. Feeling obligated to run Wanderer's Palace 10 times was pretty bad.

What would help people want to stick around in dungeons more, is to drop good crafting materials (say in stacks of 10-20 at a time), have perhaps some randomized loot in chests that's materia worthy, etc. Like, if you found ilvl 60 gear, that had 2-3 materia in it already and was convertible, that's a good way to make money. (Materia melded gear levels up faster, so you can turn it into materia faster). Dropping treasure maps on the last chests could also be useful. They have to give us a reason to do these dungeons a lot, not just because we need to hit myth cap