>>19665668That said, I like M-Swampert and look forward to using it.
I just wanted to hopefully quell what I viewed as unrealistic and unhealthy hype. Swift Swim is decent, but it's definitely not that great on Swampert.
Now, some constructive discussion:
If you plan on using Swift Swim, you can either set it up yourself (option in Single on non-Rain [ex. TR Reuniclus in Gen 5] and Rain teams).
If you set it up yourself, you'll likely run:
Waterfall/EQ/Rain Dance/Stone Edge.
In Singles I suggest using at least 2 Rain Setters, one with Damp Rock. As such, fellow rain setters are standard fare: Politoed, Pranksters, or mons like Kingdra/Ludicolo who can both setup and abuse it.
Now, in Doubles it gets more interesting; I'm going to assume the partner sets up. In this scenario, you want 2 of three things in a partner for Swampert: 1. Sets up Rain Dance 2. Reliable Setup 3. Immune to partner's move 4. Can take advantage of Rain.
Reliable setup means that it can nearly guarantee setup with Speed, Prankster, or something like Aroma Veil that lets it ignore Taunt.
3 is relevant because Swampert's secondary STAB move is EQ (so Flying, Levitate, Telepath).
Taking advantage of Rain can be anything from reduced Fire weakness, Hydro Pump/Thunder/Hurricane, Swift Swim, etc.
A minor note is the ability to support in general; things like Dual Screens, Heal Pulse, Wide Guard, etc.
After a cursory scan, here are some mons I think make for a good fit:
Bronzong, Latias, Rotom formes, Uxie, Dragonite, Crobat, Salamence, Thundurus I, Tornadus I/T, Xatu, Zapdos, Meowstic-M, Sableye, Aegislash-Shield, Jirachi, Aromatisse, Kingdra, Ludicolo, Politoed.