Falaris, your ban was justified. In fact its posts like the one above this that vindicate it.
Anywho, more on topic. I would love to try a 4x Druid defense. Stack the FC up with nature resistance and subtlety and i reckon you can get a 67% (15NR on cloak, 2xrings and magic resistance pot) chance of purge failing. Assuming that the O is wise to this and has brought 2 or 3 shamans then their damage output will fall significantly if they have 3 players spamming purge constantly. Also this would mean that they would be crutching on windshear as their primary interupts, assuming they want a hunter or two and a priest, which would have 37% failure chance (again, the healing druids would have NR). It shouldnt suffer too much from losing a mage shaman ans priest since there would be 4 sets of roots flying about thus mage isnt so necessary; CC isnt a problem, therefore friendly dispell isnt so necessary; and the shaman would be out healed.
I would love to try this, as i reckon it would be a pretty fine kiting D and druids heal good. Droods are better than shamans imo, especially when purge is less of a problem. the lack of huge heals would be compensated for the near constant hots and glyph of rejuv.