>>37435848The reasons U.B.s were shit was because there were way too much of them, and you had to play a shitty gyroscope minigame to actually get to them in the first place
Having unique NPCs that give you a boat ticket or some shit that takes you to a mini dungeon with a mythical at the end is all it takes.
The same shit worked for all the legendaries in Gen 4 & 5, even without them being mythicals, and those were cool as shit