I don't really see weather as much of an issue whether I'm using a weather team or not (that sentence is a bitch). Each one tends to carry a handful of flaws and wish it had room for a 7th pokemon. The only one I really feel to be overpowering is Rain. Sword Dance/Roost/Bullet Punch/Bug Bite Scizor, Hydration Vaporeon, Ferrothorn, Special Attack Dragonite, all just a little ridiculous. Something like my team struggles with Heatran, as well as Dragon and Fire Pokemon entirely since both resist the most common sun attacks: Fire and Grass (Solarbeam, usually). Dragonite helps against Dragon with Outrage, but Heatran still walls almost all except my own Heatran. Hail is 99% meh unless built very, very well. I love my Hail team, I've been using Hail since 4th gen so I know how to make it good, but most suck. As for Sandstorm, kill Excadrill and TTar and you're usually all set lol.