>>23552241Yes, it's more viable in Ubers than Reshiram because Ditto can revenge kill boosted shit while Reshiram is mostly outclassed by other hard-hitters in the tier. They don't do the same thing, so it's hard to compare.
However, Trevenant and Gourgeist are competing for very similar roles on a team, and Gourgeist is ranked higher; Therefore, Gourgeist is better in that role. It's not even hard to see, just comparing their stats and movepool Gourgeist gets reliable recovery and is much bulkier overall, while Trevenant doesn't have reliable recovery and is much less bulky overall.
