I wish Blizzard realized this too...
If sub rogue, frost mage, affliction lock (not a bursty class but fits with the others too well) and feral druid were not so out of control, other specs would have a chance at high rated arena too. These 4 specs combined together in several different comps like RMP, FMP, RLS, MLS, (almost counting junglecleave here too but it only has feral out of these 4) etc tear the brackets apart. All these comps have huge bursts combined with awesome cc. You just can't match their level of burst and utility with several other comps.
I don't mind them having the utility they have, nerfing that would have negative impact on this game. Why can't blizzard just realize that they have way too much damage atm? You should not have both amazing cc and ridiculous burst. RMP for example either kills or forces major cooldowns during 10 first seconds of the match (IF you don't have blanket cc classes in your team). What's the freaking point? Most of the teams i mentioned are able to from cc chains of several seconds all the time, so why the heck can they also kill in 5-10 seconds?
If Blizzard would dramatically nerf sub rogues, frost mages, feral druids burst damage, we might see a handful of other specs step up in the ladder. Just by nerfing these 3, huge amounts of specs would become a lot more viable in high rated arena. If they are better than others in so many ways, they should not be ahead in damage.