I can only by your original post but you need to be using your full arsenal in order to do well at the CM's and change talents accordingly for each dungeon. it's not clear if you are doing this but i suspect you are not as all your talk about is pure throughput of the healing spells and them not being enough.
For example unbreakable spirit i drop for many heroic dungeons and CM's for the double sac from Clemency (i find this works as a mana ‘conservant’ and saving peoples lives).
In Skyreach you can eat a beam yourself with DP / bubble. AM as a CD for one set, Cd's for another, Beacon of faith here helps immensely too. It sounds like you just need to get using all your abilities which i can appreciate you may not given the long break in playing the class. It will come
Other things to consider not put in your post, whats your ilvl / gear like? Are you doing like so many other and not bothering to enchant etc yet - this all makes critical differences in these CM's.
Are they difficult at the moment - yes but it's great and they are more than doable.
Are we worse off than other healers? No not really. AOE heals / smart heals have (rightly so) been nerfed across the board.
To the guy switching already (knightpt) i appreciate everyone can play how they want and if changing for you is what you want, best of luck and hope you enjoy the new class you choose. But giving up when you are probably not doing things right just screams fotm mate and we are less than a week into the xpac.