Not really. Most pokemon can check or counter more than one weather (Mamo beats sand and sun and can even beat on rain rachi, torni, and just plain good). If rain didn't exist, we'd be limited in building by something else. It's not like if rain left that water attacks suddenly suck; you still need water absorbants, etc. I fail to see how weather limits the meta game anymore than a non-weather meta game would imo.