Holy Feels balanced, you use all your spells for different situations as intended and there is an answer for every situation. You can fill any role of healing well enough and it feels enjoyable. (The aforementioned not including HW:Sanctuary as a spell because it is a throw rug as we all know, but that can wait)
As for Discipline, you don't want us to shield spam, fine, I get it. Then why change the mana cost and go back and forth on different hot fixes when the clear issue is it has a 3 sec CD base and no CD talented. We have a mastery that effectively is to aid Divine Aegis and if that's the case the only noticeable gain is when you crit Gheal a tank repeatedly. Our main reason for existing (PW:B) is being nerfed hopefully followed by some compensation so we aren't less good than other healers AND have our cooldowns balanced as if we are equal. You are largely discouraged from using flash heal because the other spells fill all you need to get done, okay by me. Yet this was assuming our main spell filled that role best in conjunction with other tools, where penance was better in every way. Now it's use comes down to well Penance more efficient than heal. Most don't even glyph they're main ability anymore yet still do shield glyph. You may never get it to a place where we use Power Infusion on dps again but when people use it to spam shields and ignore the cast speed bonus you may see how this all links back into the first mentioned issue(Power Infusion nerf inc, jk) I think devs had the right idea with the divine aegis from PoH but didn't go far enough with it. In fact it would be interesting to maybe have our passive mastery add divine aegis to all heals and crits double it while leaving the mastery rating effecting % based shields increase. Even if you had to make us heal for less as disc to balance it. I would be fine even if it was a mitigation healer through and through great with a combo of other healers but weak alone. Any step in that direction is better than how it is now. To be fair in my assessment Grace has been made better and more convenient by far and that was a very nice but also very necessary change. Strength of soul would be nice if other talents didn't outweigh it and I suppose this is where a blue comes in and says that this makes for more interesting decisions to which I would cough and hint at how there's a perfectly good spot over by this silly talent that we take to reduce shield CD. Rapture too has been made more effective to where its gains outweigh the shield cast by a bit, there are no more 10 procs at once but that would be irrelevant if we didn't shield spam. :)
Now there's a whole other angle that can be played on and it seems designers may take this route, Atonement. A good talent idea that I would also like to explore the possibility of, 15 yard range. Done. Exploring over. You cant base healing around a 15 yrd range on every fight it just wont work like it did on Halfus. Not healing the priest for the full amount, I get where that comes from PvP and soloing would be too good. At least make it a smart-er heal then so it doesn't heal the casting priest when there's other options since I'm sure they know how to heal themselves. It could entirely not heal the priest if it needs to be that way.(Not sure how it would go but if they make the whole play style based on atonement this would be not surprising) Now making it interact with holy fire and the divine accuracy glyph adding holy fire will be worth looking at, I haven't gotten to testing on the ptr yet but I'm sure it will be interesting. We have a spell that does a little tiny bit less damage with the dot(hot with atonement?) added in but in conjunction with glyph of smite makes for some good 18-20k heals on a crit damage smite with hf dot on the enemy. I know you could already do this and have tested it myself but now having no down time healing and miss chance involved is a nice addition. As an aside to the whole atonement deal archangel was nerfed too much, the only reason to talent it is so that when you Hymn of Hope/inner focus cast a heal/Divine Hymn or any combo of them and its going to fall off you get some mana back beforehand to stack it up again. It would be nice if it gave enough to stack it back up(the difference in cost of 1800~ to the 3k~ it costs with no stack) and then 5% added to it. My only worry with this is that atonement gets to be the thing and the top guilds (if not everyone) stack Disc priests for extra dps at no healing loss, That wouldn't fly long term.
Now I'm not saying Holy is perfect and Disc is unplayable, Holy has little irritations that get fixed. (Chakra going on CD without working, goodbye forever) Meanwhile Disc has core issues that bewilder me as to what they want us to be doing with this spec in the future.