Mind-numbing long wait times...

[Canadane]

It's an optional piece of content. It's not required.
Assuming you're not on the Free Trial, you have a tool called Party Finder for these optional things. It'll help you get some quick help (sometimes) as it'll group people outside the instance instead of inside like Duty Finder. This gives you the option, if you so desire, to have some level 90 friends just kill the thing in a few seconds for you rather than syncing everyone down to level 50.

But again, Ultima's Bane is optional. You do not need to do this content.

[Darkside345]

It was the Crystal Tower dungeon runs. I was able to finally complete them this weekend. It only took 3 weeks to get into them.