Ban weather, Ban Shadow Tag..... Bans make the game lose its difficulty, for example, a Shandera takes on fighting choiced moves, lockd moves, or anything it can resist. I never liked the choice items, but if you find a Shandera, unless you are weak to its types, it can be beaten with those pathetic stats(except Sp Atk) or send an eccentric Ditto after the sacrifice(this is the only thing that sucks to me), which is the TRUE ultimate revenge killer. Weather themed teams are sure to be common, but weather had always been common. Just send another weather into play(in a careful switch) or use it as an advantage if you can. Also, the opponent having a Shandera doesn´t mean you can´t have a Shandera. The opponent having a strong Drizzletoed and Kingdra doesn´t mean you can´t bring a Droughtails and a Chlorophyll Poke(sun is gimmick), or a Hippowdon and a Excadrill.
It is just whether you take the new advantages thrown toward you, or if you think you are good enough to take them with a pretty good strategy. That´s the only way to win.