I tried building with many different approaches to Flapple and realised that is truly awful. If GravSleep was still legal it could have a niche role on those teams but until then Flapple should never be seriously considered for a team. GenOne decided to devote his resources to help Flapple be good (if Flapple can ever be considered good). I went for the opposite approach. In the end I decided that Flapple would be best used as a
sac pivot to get a better pokemon on the field. Flapple's EV spread gives it max attack and the maximum bulk possible while also always being KO'd by +0 Gyarados' Bounce so you can get a Moxie boost by killing your own Flapple(this doesn't come into play that often but Flapple sucks so much that I wanted the option). A slowish U-Turn lets you get in a viable pokemon for free. The rest of the team is as serious as I could make given that it had to have Flapple.
Moxie Gyarados is a set that I feel is being slept on a bit right now. When it Dynamaxes it can threaten to run away with the game quite quickly (unlike Flapple). Gothitelle is a great partner for Gyarados, enabling you to take the first KO to get Gyarados rolling. Gyarados + Gothitelle is quite strong against opposing Intimidate . Gyarados can OHKO Arcanine, Hitmontop and Scrafty, negating Intimidate with another Moxie boost, while Gothitelle prevents them switching to cycle Intimidate. Gyara + Goth is quite strong against Whimsicott leads due to the threat of Fake Out + Max Airstream, which often lets you have the speed control advantage in the early game. Arcanine, Excadrill and Braviary round out the team in a fairly standard manner. I decided to go with Swords Dance Excadrill to better take advantage of Gothitelle's Shadow Tag. Braviary gives the team some extra speed control and provides another option to prevent Gyarados from being Intimidated. Shadow Tag allows the team to take advantage of Flapple's
death U-Turn to the fullest. Flapple conveniently quad resists Electric so it can switch in and U-Turn out if Gyarados is threatened with a KO. Sucker Punch is a nice move that can OHKO Dragapult, although in practice it usually misses.
I think that
this game really shows Flapple's worth.