I facepalmed so hard I have a splitting headache now - warlocks who complain about demonic portal are infuriating.
As for hunters I would like to change my answer to make further concessions then (based on watching top end hunter videos) - yes hunters take skill and yes there is a gradient of hunter skill. I have concluded that I have never encountered a skilled hunter in arenas (or rbgs) during this expansion however - which was tricking me into thinking that all hunters are bad - it's not true - it's just that all hunters I have encountered in a relevant time frame are bad.
Clearly there are very skilled hunters, but I stick to the following points as well - that the absence of truly high rated hunters in North America and the prevalence of feral cleaves (which I persist lack skill compared to just about any other comp at the same MMR) does indicate that the hunters who do reach even 2400-2600 ratings are doing so more by their being carried by ferals this season than by their skill being 80% of the skill of a top end hunter (if they were 80% of the rating for example). So perhaps it would make more sense to phrase my 'no difference between 1300-3k' comment like this - I see no significant difference in play between the hunters I face - between a hunter on a 1300 MMR team, and a hunter on a 2200+ MMR feral/hunter/x - they blow all their cooldowns and then if they haven't won they die, they don't kite my psychic screams like they should, they don't stutterstep when I am setting them up, they let me death out of scatter/traps when they shouldn't, and when my dk tries to kill them most of them use 50-75% of the tools at their disposal to keep me off them - when they should be using 90-100% of the tools available. The most significant differences I see between a 1300 MMR hunter and a 2200+ MMR hunter is gear and team composition: but not how they play their class (and for most of them they look Nothing like how top end hunter videos play the same class).
Edit: So maybe the best way to phrase this is, there is a Massive skill cap for Hunters - wherein 99% are playing Huntards (a distinct and separate class) and the top one percentile are playing Hunters (distinct from Huntards).
Edit 2: But in saying that, I'm not saying the skill cap for hunters is highest, but that the discrepancy in their gradient is perhaps widest - I'd still say while top end hunters take an impressive amount of skill, not More than a number of other classes and specs (rogues, priests, warlocks, resto shamans, etc).