Healing wave may be a long cast but there is the option for haste now since alot of the new boa gear has ahste on, reforging and also glove enchant may allow them to stack some useful amount. not to mention trinkets. but the main reason for them being superior is that they will be able to dispell purge shock earthbind and earthshield. We can speculate all we like but until its released we can only rely on what our fellow twinks come up with on the Beta. =(
Oh, im sure they will be great on O in cata and decent as offensive healers in arena, however they will be poor on D. Both paladins and priests get a spell equivalent to healing wave, aswell as other, better spells. The shaman will still have great utility, just not so great for defensive healing due to their low throughput.
