I recently stacked some crit gear on my poor unsuspecting shadowpriest and turned him into an LOLSMITE machine. I enjoyed the change of pace in playstyle, but I was really just turned off of the whole idea because of all the limitations. Smite was a subpar nuke, holy nova was in most cases just a huge waste of mana, and holy fire was a laughable excuse for an immolate-function spell, despite it's cooooool animation.
With the new changes to Holy fire, being:
Consumes the enemy in Holy flames that cause 890 to 1130 Holy damage and an additional 350 Holy damage over 7 sec.
290 Mana, 2 sec cast, 30 yd range, 10 sec cooldown
knock that 2 sec cast down to 1.5 with 5/5 Divine Fury, I feel that this will do a lot of good for holy priests. Although I would to have loved to see a talent along the lines of "Holy Fire increases holy damage done to the target for the DoT duration." to give it a little more raid/group synergy (albiet, only with paladins), I think this is a step in a positive direction. Before, if you touched holy fire once during a fight, you were either making yourself a huge "HEY! I'm casting a huge long spell, and if your interrupts aren't off cooldown, they sure as hell will be by the time I'm done with this spell" beacon in pvp, or significantly reducing your DPS in pve. Now it seems like we will have a more positive spell rotation that, at any rate, will aleviate some of the boredom.
As for talents that'll increase the viability of Holy DPS, there are a few changes that really look positive. Moving Enlightenment down to Tier 6, and the added +5% to spell damage, was a fantastic move. Also, twin faiths gives another +5% spell damage. Along with Imp DS, and Spiritual Guidance, you're looking a ton of damage from talents alone.
Looking at the shadow tree as a dump for spare points (with 5/5 reflective shield, 1/1 PI, 2/2 Surge of Light, you're looking at 8 extra points), Spirit tap is going to be key, especially for leveling. The spirit bonus not only MORE THAN DOUBLES the extra spelldamage you get from spirit (including the +10% spell damage on top of the bonus), but allows your mana regen to tick away while you're still casting. The only grievance I have with Improved spirit tap is that it'll only proc on shadow crits, which won't benefit from the talent that increases the crit chance of your holy spells. Granted those two spells are on a cooldown, so it makes sense that you wouldn't be able to chaincrit holy nova on your group and get that +50% regen infinitely. However, including Holy Fire to the improved talent would keep it balanced, give it more synergy with a holy DPS spec, and make this holy dps build a heck of a ton better.
All in all, I think that they improved the viability of this build a bit, but it's still not on par with the damage, utility, and CC shadow offers. The only way to make this a lucrative choice for priest specs is to accentuate the fact that you can pump out some healing along with respectable damage. Although, I feel like you really have to sacrifice one for the other, and a true hybrid holy dps/healer won't give a huge advantage over just speccing for one or the other.
Edit: Also, I think it'll still be a joke in PVP, unless you consider a dreamstate-like healing hybrid build. That actually might not be bad to look into...