@ Jexulus and Melee Mewtwo: I'm sort of in between with what you guys said. To me (at least for now) it seems like the new ubers metagame is very tailored towards bulky offense rather than stall or hyper offense. Because of that, when looking at bulky offense teams, the nerf to weather doesn't really seem to have changed much. Hyper offense teams with pokemon like Kabutops or Venusaur suffer because it is no longer about just taking out the opposing weather inducer and sweeping with the pokemon's weather boosted speed. If defog didn't exist than stall would prevail, but since it gives those hyper offense teams a way to just get rid of your 3 layers of spikes, 2 layers of toxic spikes, etc so easily, I feel it makes people a little more reluctant to go through the hassle of putting down entry hazards. Of course things are never that cut and dry, so let me explain a little further.
Stall players use a lot of psychological warfare. Many times it is less about beating the opponent and more about breaking their spirit and causing them to forfeit. See, the best stall players give the successful appearance that their team is invincible, and they will slowly take down your pokemon, one by one, as you hopelessly try to take down theirs.
On the other hand, the best offensive players realize how the best stall players operate and know it is only a matter of time until luck becomes part of the equation. If a critical hit happens about 1 in every 16 turns, then the more time that goes on the more likely it is for that offensive player to get that perfectly timed critical that can cause them to defeat one vital pokemon on the stall team, regain momentum, and gain the confidence that hyper offense teams rely upon.
Basically what I'm saying is that the weather nerf has eliminated most forms of hyper offense, but defog has given offensive players another means of regaining confidence against stall teams, thus, in my opinion making stall a little less viable.
Less Hyper Offense+Less Stall=More Bulky Offense
And with regards to the sun, there were just as many bulky offense teams as hyper offense teams, possibly more, so it hasn't really changed all that much.