At the end of S5 and start of S6, my 3v3 teams played RMP exclusively and while we were a tier below the very best RMP team in our BG (that would be Billian/Versica/Rexsteele), we were still very competitive about cheap WoW Gold, as in top-20 gladiator competitive. Then we added a DK friend to the roster, my mage started playing is druid alt, and my priest started playing his DK alt. Before we know it, their "alt" warrior/DK/druid team broke 2600, and our DK/rogue/priest became the go-to comp for our own 3v3 to get cheap WoW Gold. 

We tried to run RMP again to build up our mages PR, and tanked 200+ points in the process.  Our CCs sucked, our burst coordination was non-existent, and we lost to every comp.

After tanking the first 100 points as mutilate/frost, we tried FOK/frost and this is actually was not as bad as I thought it would be about cheap WoW Gold. Deep freeze and improved counterspell coupled with FOK interruptions allowed my mage to spend his free casts on frost bolts instead of sheeps (he still occasionally sheep people that are out side of my FOK range). He has multiple 50% health targets with wound de buff on to choose from, and can nuke whoever he wants to get cheap WoW Gold. This is very similar to FOK in 5v5. We did not really lose points but did not gain any either.

However, because frost is a single target DPS spec, we do not have anywhere near the AOE damage pressure DK pestilence brings to the table. For RMP to work with FOK, I actually think the mage should go fire. Living bomb, dragon breath and of course, blaster wave make amazing synergy with FOK. When we played DK/rogue we had a much easier time beating cleaves going on our priest, not because we had better peels or defensive CDs, but because we dished out so much AOE damage on two melees stacked together. Fire/FOK will be a very interesting twist to the existing RMP formula to get cheap WoW Gold.