I'm not sure a tougher Drought starter would necessarily 'break' sun; I daresay that even with a starter on the same level as Politoed it would still lag behind rain. If nyttyn's Politoed summary were reversed we would be getting somewhere - if Drought had been given to a Grass type instead of a Fire type, it would effectively be able to switch in, wall and threaten water types in the same way that Politoed can with Fire. But it wouldn't make sun overpowered; sun's flaws run deeper than just its starter. What does rain have that sun doesn't? Well, for a start the Water type in OU covers a lot of ground; there is little that Politoed, Starmie, Gyarados, Tentacruel and Jellicent have in common besides that Water typing, and a vast amount of other Pokemon fit onto rain teams very naturally (Scizor and Ferrothorn appreciate the Fire nerf, plenty of sweepers appreciate 100% Hurricanes and Thunders). Additionally, Water types are commonly given Ice type coverage moves, allowing them to retaliate against Grass type counters. Sun teams can't draw from so rich a well; most of the available Pokemon are offensively oriented. In terms of defensively oriented Fire types there are pretty much three - Rotom-H, Torkoal, Victini at a stretch and, errr, Magcargo. Where rain teams have Rain Dish, Hydration, Dry Skin and probably other defensive abilities, sun teams have Leaf Guard. Which kind of sucks. Certain typings come associated with certain playstyles because of the trends within that typing. Perhaps when the time comes to consider exactly which typing CAP5 will try to raise into the metagame it should be determined which of the more underused typings is home to the most varied range of Pokemon whose viabilities are undermined primarily by their typing - it's key that we ascertain whether a typing's lack of metagame presence is due to its inherent qualities or simply because its representative Pokemon wouldn't have been any use in the first place. If CAP5 tries to boost usage of a type with the latter affliction it's doomed to fail from the beginning. Edit: ganj4lyf beat me to the punch. Fair play.