As the only class that has two talent trees devoted to healing, it is inevitable that some priests who try to understand both healing trees will confuse things along the way.
It’s no secret that it can be very tricky to switch from one healing spec to the other. You’d think it would be fairly simple and straightforward; After all, most of the spells are the same for both specs. Binding Heal, Flash Heal, Prayer of Mending… these are all spells that should get quite a bit of usage no matter which spec you choose as a Priest.
However, the different synergies between talents for each tree means that the healing style is completely different for a Disc Priest as opposed to that of a Holy Priest. Or rather, it SHOULD be in order to use your talents in the best way.
While I’m sure there are some Disc Priests who respec to Holy and don’t adjust their healing styles properly, it seems to be a much bigger issue for those going in the opposite direction.
There are three distinguishing features of the Disc Priest who is still healing like a Holy:
Rarely Casts Power Word: Shield – It’s not that Holy Priests don’t ever use bubbles, it’s just that in a raiding environment they aren’t really that useful, and they are expensive. We only have one gimmicky talent that ties in with Power Word: Shield. This is undoubtedly one of the more difficult things to become accustomed to when you switch from Holy to Disc, so expect there to be some learning curve for new Disc Priests as they figure out a good bubble balance. In a raiding environment, at the very least, a Disc priest should be bubbling often enough to maintain Renewed Hope on the whole raid.
Tries to be a Burst Healer – Holy Priests are designed to do burst healing and too many respec to Disc just to get the awesome Penance, and still heal exactly the same - nothing says healing burst like Penance! Of course, this can work – particularly if the group outgears the instance. I told a story not long ago of a Disc Priest who did exactly this. However, if you are trying to be a burst healer as a Disc Priest, it is highly likely you are not taking full advantage of your abilities and strengths. Power Word: Shield and Penance are the two staple spells of the Disc Priest – and both need to be used.
Proudly tops the Healing Meter – There are reasons a Disc Priest could be at the top of the healing meter that are completely legitimate. In general, however, there's a good reason why Disc Priests usually show up at the bottom. If you have a Disc Priest who is proudly spamming the healing meters and bragging about how they are at the top of the healing meter, then it is quite likely they are officially Missing The Point. When I'm specced Disc, if I'm at the top of the meter, I'm asking the other healers what's wrong.
All of these features tie into the same basic concepts. Holy Priests are bursty healers who can top charts and focus on green-bar-go-up abilities. Disc priests are mitigators, and until healing meters accurately reflect that ability, they will likely continue to be at the bottom of the healing meter.