The low level Holy Priest's Talent selection is frustrating because many of the talents do not apply to low level healing necessary in Random Dungeon Finder groups.
I know that the Light Well spell is improved and easy to use, but at levels 30-40 there's really no reason to use it. I plopped it down and the couple of people that used it, ran up right next to it before clicking it. So be ready to tell people how it works.
Empowered Healing and Improved Renew. I'm not sure why they didn't just roll the renew buff into Empowered, but renew will be a low level holy priests friend. Heal takes a long time to cast, and Flash Heal will eat your Mana up fast.
Note: Renew is good for the tank or anyone else taking constant damage. Casting renew on everyone that takes a hit will eat up your Mana. Use the very mana efficient Heal spell to top off a player that took a hit.
Divine Fury. Faster heals is a good idea. Still the Heal spell ends up being a 2.5s cast which is a long time when the tank has pulled too much trash. Keep refresh running, when the tank starts dropping hit them with a Power Word: Shield spell, then start the 2.5s Heal spam. A shield + heal is less mana then one Flash Heal spell. Also, the shield is sometimes enough to let the renew catch them up and a heal isn't necessary. It's okay to cancel the heal if it looks like they aren't going to need it.
Inspiration requires a critical spell hit which at lower levels requires spamming Heal. Not real useful.
Surge of Light has a very low proc rate, which would be fine in a raid, when heal spamming is going to happen.
Desperate Prayer. Free self heal, not exciting...
Divine Touch... Renew is great at this level, any extra healing from it is great. Pop in the Prime Glyph of Renew for even another 10% extra. Here's what I do, let the tank pull a group, they will drop a bit, hit them with Renew. This allows the direct heal to land, plus allows the tank to establish could aggro control. The smart play isn't always to keep the tank topped off.
Holy concentration. Mana can be a problem especially in low level Random groups where Aggro Control is not always great.
That's it. Two very useful talents, Improved Renew and Divine Touch. Three okay talents, Empowered Healing, Divine Fury and Holy Concentration. The second level (Desperate Prayer, Surge of Light, Inspiration) barely register. Lastly, The Light Well, which shall always seem like a great spell but is just not useful at the lower levels.
Forcing a player to stay in a single tree at lower levels prevents some very effective low level healer builds. It's Frustrating to spend a talent that's not going to be useful until I'm healing a heroic.