What's scary about these statistics is STAB and rain-boosted attacks, which results the following: Politoed's Scald hits a neutral foe essentially for super effective damage. If a Pokemon resists your STAB Hydro Pump in rain, you still deliver 120 BP's worth of damage, which just goes to show how powerful rain has been in BW. Fortunately the metagame has evolved multiple times throughout the last couple or so of generations that we see new Pokemon introduced to make the game more diverse. Sand has been one of the staple strats for three generations straight, and was provided with a handful of goodies in BW (Terrakion/Landorus). DragMag, as referred to, is a very formidable strategy to use when built properly (you don't even have to use Magneton/zone, by the way). Even sun has proved it can, if used and structered efficiently enough to deal with weathers by including Dugtrio, hold its own against the best of teams. A Pokemon like Genesect shattered teams apart on its own. It took one place in a players' team, which meant you had five other members to really take advantage of its biggest assets and strong points. Politoed cannot do the same in terms of slaughtering a team single-handidly, and when dealing with a team based around rain, it has one route of action and that is to abuse its weather, whilst maintaining it. You can say well, add Terrakion and Latias to deal with sand and sun respectively but you can do the exact same with the other weathers. For example, Sand can run Keldeo. It may have not been the easiest generation to adapt to competitive battling and I'm sure the council will do its best come Gen 6 to produce a well-rounded metagame for us all to enjoy but Pokemon itself is always evolving and you can't expect, with each generation that is released, for the metagame to get progressively weaker; more threats equals more potential strategies worth checking.