OK, Hoenn is officially my favorite Pokemon region ever.
Hoenn is the best, I agree.
And yeah, Team Preview is what Blade said. It ruins the role of the lead pokemon, because if people see your team they'll guess as to a lead pokemon (like Azelf), so leads are not common anymore. It does add one more elemnet to the game, because you have to try to get the best possible matchup.
I never understood why Excadrill was such a problem. Probably because I don't play competitively. But these days, people seem to have a weather starter of their own, so switching the weather beats Excadrill. Also, Mach Punch (from Conkeldurr for example) hits super effectively.
What would make more sense is to send all weather starters to Uber, and keep OU as a weather free zone, or have a seperate OU for weather free battles.
Landorus and Terrakion are still strong in sand, and Tyranitar will always be strong. Garchomp without sandstorm isn't that amazing. He's fast and strong, but without a 20% chance to miss him all the time he'd be just another 4x ice weak dragon.
those are just my thoughts, though. Smogon seems to be very ban-happy lately.
I wouldn't say its a disadvantage, so much as just another level to the battle. Both players get to see the other team, so its even. And many pokemon run different sets in battle, so you don't know the opponents team 100%. As I said above, it really only hurts lead pokemon like Azelf, Machamp (though he suffers from Conkeldurr usage) etc.
Huh. That's odd. I guess it's only fair, though; we've been doing it to Gym Leaders and other in-game Trainers via Bulbapedia and other sites pretty much since the internet was invented, so it's only fair that we have to face that particular disadvantage ourselves...
In other news, I just won a Battle Factory-style thing in the Battle Tent at Slateport. My rental team: Breloom, Golbat, Electrike.
