I prefer to be a healing priest. But a healing priest works best with a group. While I have a guild, my hours have made me far from first choice when groups are formed – and when I could do groups others were either involved in other things or offline.
Holy-Disc can grind. Just not – in my experience – as well. There are exceptions to this – players who just hammer things with their light. I strongly suspect that’s the player, not the spec.
Case. I am still making mooncloth because I WILL be a healer again. But I grind the mats twice as fast — especially the primals. I’m not particularly well geared and I’m still doing a sustained 350dps over half an hour of grinding — including hunting for the next mob. Fight DPS has reached as high as 600 dps. And again, I’m not that well geared for shadow dps.
It’s frustrating. ah well.