How has B/W changed the metagame?

I haven't played any 5th gen competitive due to losing interest, but Swift Swim is extremely powerful and does deserve looking at. Rain is hands down the best weather in the game. Sandstorm only increases Sp.D for Rock, a generally weak defensive type, and does some minor damage per turn. And yet it's enough to give your team a significant advantage. With Swift Swim, Rain does 3 things for your Pokemon:


1. Double STAB (2.25x) damage on ALL Water attacks, stacks with +Attack bonuses
2. Double Speed stat
3. 100% accuracy Thunder/Hurricane, if you're running it
So it's effectively better than a free Growth and a free Agility. I mean, that's pretty fucking good.

So to recap:

Rain Dance:

1. Double STAB (2.25x) damage on ALL Water attacks, stacks with +Attack bonuses
2. Double Speed stat
3. 100% accuracy Thunder/Hurricane, if you're running it
4. Activates numerous abilities: Dry Skin, Hydration, Rain Dish, Swift swim (point 2)
5. -50% fire damage

Sunny Day:
1. Double STAB (2.25x) damage on ALL fire attacks, stacks with +Attack bonuses
2. Double Speed stat (chlorophyll)
3. Kills off the accuracy of Thunder/Hurricane (down to either 40 or 50, conflicting reports).
4. Activates numerous abilities: Solar Power, Leaf Guard, Flower Gift, Chlorophyll, Dry Skin (negatively), and... once again chlorophyll (point 2).
5. -50% water damage
6. Instant solarbeam.
((So fire types can weaken their rival water types and if they have access to solarbeam, can take em out instantly, water types get nothing similar (due specifically to rain dance!) to deal with threats against them.

Hurricane: To take out threatening grass types, but the only pokemon that get this that are also water types are water/flying... which aren't threathened by grass.

Thunder: doesn't counter any water threats that I know of.))

7. Moonlight/Synthesis/Morning Sun +recovery. (50% ->67%)




I dunno~ Both sunlight and rain seem rather nice. It's not that one weather is technically better than another (though tbh, it almost seems like sun > rain).