Mega Swampert might honestly make dedicated rain teams a bit broken, so long as they don't absolutely botch its stat spread, but it'll be hard to fuck up 635 BST+double speed. And you know it's going to get a fuckton of attack, because jesus it looks like the Hulk.
Keep in mind that Rain is already quite viable and actually pretty hard to beat with anything but full stall teams.
-Even if Gamefreak is an ass and lowers its speed, at base 40 it will still outspeed base 110's and at base 45 it would still outspeed Greninja. While running Adamant. And those extra points needs to go somewhere
-It will be immune to Thunder Wave, meaning m-muh prankster genie won't stop it
-It has no issue beating Tyranitar. Charizard-Y is a shaky check, since if you mega evolve in front of it and summon sun, it still outspeeds you cause turn order is pre-determined. It can KO you with pebbles+waterfall, or just use Rain Dance and force you to stay in cause you're charging Solar Beam. If it's already MEvolved, Politoed counters
-It's base form is really bulky and its mega evo will be even bulkier, and it only has one weakness
-Mega Swampert only needs 165 attack (+55) to hit as hard as Life Orb Kabutops, who is already know to be quite a nightmare in rain. Rain boosted waterfalls off of 165 base attack+Adamant nature will hit as hard as Jolly Life Orb Garchomp's Outrage
-Almost perfect coverage from STABs+Ice Punch, only missing out on Rotom-W who is not much of an issue for rain teams anyway. This leaves a free slot for Rain Dance or anything you want to hit particularly hard, e.g. Stone Edge or Gyarados, Low Kick for Ferrothorn, HP Flying for Chesnaught (a boost to SpA would actually be useful,) etc. It actually has a pretty good movepool. Yawn is trolly
-It has PEBBLES
I don't think M-Swampert itself will be broken, but it's going to make Rain teams that much harder to handle.
>>19542963>Y-zard>dominating OUlol
