No. That's it. I'm done. I kept quiet last time people argued for this because I had already argued for dropping it and didn't feel like it was necessary since PK seemed to be on my side. Gastrodon is NOT GOOD IN THIS META. He's complete setup fodder for almost all setup sweepers except for Lucario and Thundurus-T. He certainly can't switch in on setup sweepers. Example: Dragonite has Multiscale up and uses DD. Gastro switches in, and eats an Outrage to the face only to do pitiful damage to Dragonite with Ice Beam. Not only that, but most banded Pokémon can at least 2HKO it anyway (some like Dragonite, Kyurem-B, and Haxorus can OHKO with prior damage).
But the real reason Gastrodon sucks is that this is a Landorus/Keldeo/Breloom metagame. Gastrodon is 2HKO'd at least by all three of those, and is easy setup fodder for Breloom. Not only that, but because this is a LKB metagame, Celebi is also everywhere. Ferrothorn has always been a staple as well, as has Venusaur. People don't really prepare for Gastrodon (cause they really never have to). But they DO prepare for Rotom-W, so Grass types are surprisingly common, and all of them beat Gastrodon. YES, he has a niche. But he doesn't deserve to be up there with some of the best walls in OU like Jellicent and Amoongus. Keep it C Rank!