If there is an auto weather affect, one can always just run an auto rain team, with things like Bulk Up+Focus Sash Floatsel which can guarantee BPing a Bulk Up with its insane speed as well as a Mixed Kingdra. With things like Gorebyss and other massively fast things people could easily get in boosts. Lanturn could serve as a pseudo rain dance 'counter' with STAB 100% accurate Thunders and free recovery off of water attacks, but if you have a rain dancing team Sunny Day teams have an inherent disadvantage. Especially if you do things like put Flamethrower Slowbro and other fire attacks on your team to take care of SolarBeaming Grass types. The sheer power you could have with Auto Rain Dance teams is simply staggering, and I wouldn't support that.