To be completely honest, I haven't seen (in my limited experience. I'm limited by being unable to actually battle more than a few times a day, because of school and such.) much of Defogging, because once I get SR and a layer of spikes up, anything that switches in is weakened enough to one or two HKO. If it flies, its weak to SR. If it resists SR, it takes decent damage from spikes. (except Skarm.) I get up my hazards, then begin sweeping through the enemy team with ease. One time I got up SR and three layers of spikes, and they had no Defoggers, only a Forretres. So naturally, my +1 252 SpAtk Porygon-Z proceeded to 2HKO it with Thunderbolt, thanks to hazards, and getting a hit on the switch in. Only with max hazards was I able to prevent my hazards from being cleared. Kinda ironic. Their Forretres was doomed by what it was sent out to clear. And from that moment, they were royally screwed, taking 37% damage on any switch in. Hazards are extremely welcome on my team, as they allow me to KO quicker, and keep more momentum, and therefore keeping them from removing them. But they aren't so crucial that if I lost them, then it's gg. I just push through their Defogger/Spinner, and keep right on sweeping. They can change a lot of 3 or 4HKOs into 1 or 2HKOs, but aren't neccesary. The point in this, is that while hazards are nice, the meta isn't centered around them and their removal. On that note, I haven't seen much hazard usage from others, so usually I set up hazards, then let my hazards/spinner die, since I probably won't need him again. Even if someone DOES set up hazards, it's usually just SR, which doesn't completely cripple me, and I can simply push through. Or if they remove mine, The time they took to remove them allows me to get a free KO. I personally find Hazards/Defog/Spinning to be pretty balanced usage-wise.