>>29935773Even really good Pokémon on paper end up in PU: Zebstrika, Floatzel, the elemental monkeys, Rapidash, Raichu, Mr. Mime, Dodrio, Gigalith, and Cacturne, to name a few.
The tiers are a lot more selective these days; Pokémon that were in OU now are now in UU or RU, Pokémon that were in UU two generations ago are in NU or PU, etc.
Unless it really impresses, Decidueye isn't going anywhere. And right now, it has a decent movepool but really terrible defense, speed, and defensive typing. Hell, Trevenant and Gourgeist (all forms) are currently in PU.
The standards have risen and Decidueye doesn't seem like it will be anywhere near the top. It may hit NU, but I doubt it is going anywhere higher.