TOLSTOY BELOW - READ AT YOUR OWN PERIL
To necr... I mean, revive an old thread, I'm interested in hearing some people's opinions on the new Disc changes.
I myself am not able to log on until either Friday or next Monday/Tuesday (new computer being shipped, this POS I'm using can't handle WoW), and did not play the PTR or Beta, so I am unable to give any first-hand experience. So this is largely educated guessing based on changes made, not the definitive account. Feel free to reply and disagree with my assertions!
You may notice a distinct lack of QQ. That's because I'm eager to break out of the bubblebot role and into something more interesting, which this patch appears to deliver.
Power Word: Barrier looks like an amazing cooldown. For PvP, the uses should be pretty obvious - throw it over people taking damage, especially yourself. Use it liberally. For PvE, I can see it being extremely handy in many situations. For example, if you don't have a lot of bubbles up for an Infest phase on LK (perhaps you were just released from a Valk) and there is not a Defile soon (so everyone is relatively grouped up), you could drop it in help keep that Infest from sticking. Another example would be, well, anytime melee are taking lots of damage - maybe multiple Marks on H Saurfang, or perhaps Sindra phase 3. Since it's more powerful than a regular bubble, it will probably see use as an emergency tank-heal as well.
Holy Nova no longer is party-only, and instead divides the amount healed equally between all the people within its range. This, coupled with the new Holy Nova major glyph (reducing its GCD by .5 seconds), makes it much more useful to a raiding Disc Priest. I can't testify to its power, but it now has an interesting mechanic and the potential to become a staple of Disc healing. I'm eager to hear others' opinions and experiences with it!
The changes to Heal and Greater Heal, along with several new or reworked talents, make our single-target healing potential much much higher. Again, I'm interested in hearing others' opinions and experiences with our new single-target arsenal - which heals are most effective for different situations, and how powerful they are compared to other healing classes.
From what I've read, Holy Paladins got a nerf to their single-target healing (especially with the Beacon change, a single Holy Paladin can no longer keep up two tanks by themselves) with some nice AoE potential to make up for it - and all the other classes recieved serious boosts to their single-target healing capacity, especially Holy Priests. Discies seem to be one of the specs best-suited to taking up the tank-healing torch in the abscence of Paladins (who are still very strong) thanks to DA procs and talents like the new Renewed Hope.
Rapture has been changed. It returns 2.5% of total mana with a cooldown of 6 seconds (down from 12 seconds), but no longer can trigger multiple times at once so the much-loved Rapture Trick is kaput, and it no longer invigorates your target with mana or whatever resource they use.
Speaking of mana, Shadowfiend and the Replenishment raid buff both return substantially less mana than they did in 3.3. Spirit now returns substantially more, and of course MP5 has been converted into Spirit. I doubt we'll be seeking out Spirit, especially since most of our mana regen is still based on our maximum mana. This may change at 85, as I said I have yet to play the Beta.
Our haste has been changed drastically. Borrowed Time only grants 14% haste (down from 25%), and the Enlightenment talent, which granted an addition 6% haste at all times, is gone. This means we need, with full raid buffs and 0 points in Darkness, approximately 25% haste from gear to be GCD-capped. If you are a bubble-spammer, get ready to reforge or otherwise seek out more haste rating.
I'm also interested to hear people's experiences with a Smite/Atonement spec, be it for soloing, PvP, heroics, or raid bosses. While it is possible to not pick up Atonement and Archangel, the question is will we need it or not.
A lot of our spec decisions are also based around how useful Heal and Greater Heal are, as there are two talents late in the tree that rely on their usage. More on this when I actually get to use those spells in their new form!
That's all I can think of off the top of my head.