I have to admit this type of thing has always intrigued me, especially since some weather abusers (real and theoretical) are often the best counters of the weather they abuse. Heatran can use the Sun very well, but can often be a full stop to Sun teams too. I feel like I don't need to mention so many Rain abusers, who often carry hard-hitting Hydro Pumps and Thunders and usually hate taking those to the face to boot. Or even Ferrothorn in Rain. If you look at theoretical Pokemon, a different Dragon/Water than Kingdra could serve similar roles as it, countering and also abusing Rain; same with, say, a Grass/Fire type in Sun. I'm not sure if what I said is the entire intention of this concept, but it sure in an interesting side note.