there are some fights that cant be outgeared, or at least not fully. I reckon Anub Rekhan in TOC.
But there are not much of these fight as they need very special boss mechanics and we dont want all fights to be somewhat equal.
So since that isnt an option, blizzard has to measure the difficulty of their heroics, so people will be able to handle them.
The skill differences in players varies a LOT and also the willingness to put effort into solving an instance.
So no matter what they will measure, there always will be dudes posting "OMG you serious blizzard? how is one supposed to solve this???" while other post at the same time "Oh well, it was fun for 2 days, but then i got one epic and all was roflstomp".
As you can see at the numer of whining threads, telling us that heroics are too hard, that blizzard really did a jump in diffculty compared to WOTLK. And again, judging the number of whining threads, they almost overdid it.
Well not for me personally, since i tend to play with capable players, but for the majority it seems to be right at the edge or even slightly over it. So in my eyes they did a quite good job. If you still arent forced enough to play out all your skills, then you need to think of a way to do that yourself. E.G. Ignoring CC, bringing one player less, having a twink healer, wearing some greens, laying down shield, not buffing and pimping, taking out the non combat pet which reduces your resistances, ... there are endless possiblities to tune up difficulty for yourself, and by adding those you can gain a large variety of difficulty increases, to fit your needs.
If you are bored after 9 days of expansion i can tell you that you probably are near to sick of wow and will cancel your sunscription somewhen soon anyway.