heroics, your gear should be halve decent, but not needed to changed Spec...
a 41\20 BM/MM spec is fine for heroics, just place your trap early, and if it does resist's place another one, run to the other side the room if you can and wait...
A SV spec is VERY gear dependant and is quite a hard spec to work around...
But a BM spec shouldn't be to hard in heroic's!