So I've done more fiddling - I am now heroic ready and have already succesfully beaten 3/4 bosses in heroic Stonecore. Latest findings:
Levelingwise, disc beats holy. After three full zones I think I can quite safely say that the most effective rotation is Holy Fire > 5X Smite without using Archangel (with the Holy Fire glyph, obviously), then continueing to Smite the next mobs with 5X Evangelism up and only using Archangel if Evangelism is going to drop anyway. Holy has more readily accessible burst because Smite Chakra basically equals 5X Evangelism, but doesn't have such a huge ramp up time - the problem with the spec really is that you just run ouf of mana after literally three or four mobs; as disc you tend to get lowish (20%) after a mob or 12, which is just enough for the average killing quest.
Dungeonwise, I've realized the following: get items with intellect and spirit on them. Cata made the line a lot thinner (to the point of invisible, frankly), but stuff with no spirit (AKA: gear with only int and a combination of haste, mastery or crit on it) simply is caster DPS gear. You
need that spirit to function properly, unless you're a really high calibre player - and even then the slightest mistake in any 5-man means a wipe.
Specwise, I've got some interesting news. I'm glad to say that I've found that pretty much every spec is viable enough to do stuff with, but it would seem as if Archangel is the weakest link for disc specs. On some fights you'll be able to get 5X Evangelism up, but even without using Holy Fire, in *real* fights that are actually hard, Smiting is so un-viable that it by far does not warrant the five points it takes up. You can easily drop all those talents and not notice that you've lost something. If Atonement doesn't receive some kind of huge buff, we'll see very few Smiting priests.
Specwise 2, what I've been playing around with as this is
this. Yes, there's one open point - I'm attempting to see if I can get by with 2/3 Rapture now that the talent has been nerfed to hell and back, at it definitely seems I can - which means my last point can probably fill up Empowered Healing. For holy, I've been running with
this, which I suspect will end up being the main raiding build. There's no shame in picking up Veiled Shadows with that spec, just as you're virtually completely free to drop Spirit of Redemption - there's just a lot of personal customization possible, and something like
this would probably work quite well too. The only thing to note here is that PvE'ers will want to drop Desperate Prayer. At 85, with around 5K spellpower, it heals for about 10K health - which is a meager 10% of your health pool, if that. It's cool that it's free, but since it uses a GCD, you're generally better off throwing a Renew on yourself instead. If doing so means you die, then Desperate Prayer likely wouldn't have saved you anyway.
Last but not least, I need to share this
awesome trinket that I got with you guys. Epic in all senses of the word, aside from it being uncommon. It actually works so well I should be using that until well into tier 11. On a little footnote, 'is cancelled' in this case also means 'runs out'.
Sorry for the huge wall of text, but I just had to put down my findings somewhere - am getting more and more eager to start on that sticky, but I will need to do more exploring and would definitely like some discussion with the findings you guys have made.