Most frost pvp builds use Imp Counterspell. This provides 4sec complete silence to casters. Against other mages this a must. But against healers, spriest and warlocks the untalent counterspell provides 10sec lock to that school of magic.
I see many frost mages those days using untalent Counterspell. They can simply have pve build but makes wonder if Imp Counterspell really worth for pvp.