As a Disco Priest I love the changes and the thought of raiding in Cata.
Loving the new Smite mechanic, and with the right tinkering my Sheild is not that much different to pre-patch.
I do think that any raid benefits from having a Disco priest, even after the patch and for the forth coming new raids, I have found myself using more multiple heals in raids but I dont mind this, better to be actually healing then spamming PWS.
I see Disco as a tank healer in cata, 5 mans will be .....interesting, but with every change comes the possibility to learn new things.
My only complaint of the new changes is the GCD on PWS, it is not constant and can change throughout a raid/boss/mob.
Therefore I refute Darieths biased opinion (Hes Holy at heart and we know it) and look forward to proving Disco is the way forward in cata.