This thread is not completely well based. I mean, of course brightpowder plus sand veil plus sandstorm can be anoying.
But not sub. I mean, you use this tactic to try and pull out a substitute (but substitute doesn't help increasing the evasion). Then with a sub up you try to swords dance so as to do a sweep.
In my opinion using this tactic means that you are a noob. Also I feel that people who say ban garchomp are noobs as well (they are not good enough to stop it). Of course garchomp can be deadly, but after you work to get an advantage position, and this is done by many other pokes like metagross, infernape, tyranitar...
Also, If you look at statistics. So as to get a free sub up you will need 3 turns, wich means you sacrifice 50% hp. No big deal in my opinion. And if they sub/swords dance on the switch that's because you got outpredicted and that's only your fault. Also if you carry sub-swords dance your movepool is limited enough to be 100% safely countered by many common pokes.
Example: hippowdon vs chomp
sub-ice fang
sub-ice fang
sub-ice fang (miss)
switch to skarmory-swords dance
outrage/fire fang/ fire blast/ whatever-whirlwind
So your skarm will be at 50% and chomp at 25% (and can be hurt on the switch when they come again). Not to mention that they are not super fast since they don't pack choice scarf. Wow I'd love to be at this position, I can even roost. And even if you aren't lucky, statistics say that most of the times the advantage will go for you. And maths don't lie, so if you insist to use this garchomp, you will be fighting against chances, and in the long run that means losing.
What I want to point out is that every single garchomp version can be stopped if you are smart. Just scout to find out which kind of garchomp your foe is (just like heatran or salamence). I'm not saying that garchomp is a bad poke. It is good, but it requires skill to play with/against it. And if you get crushed by it, that's because your oponent played better.
I hope that this is clear. I wouldn't like that chomp was banned due to a poll where most people are noobs that don't understand the game. Please, don't make us, pro-gamers, have to stop using our loved garchomp. And if you fear garchomp that much you can always use it yourselves (I bet you have, but you have found out that you can't use it as well as we do that you want to ban it because you are jealous. You want to ban every threat to your stallish game style).
I know this post is offensive for some people, but I attemted to use logical reasoning. You offend me as much when you say that I win because I use garchomp.