Wobbuffet

Due to the fact that the one thing that would make Wobbuffet usable, Shadow Tag, is banned, it's no surprise that it is completely useless in the PU tier. Wobbuffet has a shallow and predictable movepool, and it can't directly attack the opponent. This means that Wobbuffet is complete setup bait, can easily be chipped down by status conditions, and, above all else, is completely invalidated by its foe switching out. Many other walls, like Regirock and Jellicent, do a much better job at dealing with strong attackers because they can actually attack the opponent and have better utility options like Stealth Rock and Will-O-Wisp.