I have played my priest as an alt for a while, and I kind of liked the idea of disc, but I found it lacking something. Too many encounters just don't require much in addition to atonement healing, which I find kind of boring and repetitive. I started thinking about how to improve the discipline spec and got an idea about a mechanic which would give some depth to the spec.
Every time you cast an atonement ability to damage the enemy, you gain a stack of a buff called Synergy. It caps at 5 and at 5 stacks, you can use the synergy for a new ability (or to empower an existing one but I find that a little boring) to cast a big aoe/st heal. Now, the catch is that it works the other way around also, after you have used your synergy heal, you can start ramping up the stacks again, but this time you gain synergy for healing spells. At 5 stacks of Synergy, this time you can use it to empower Holy Fire, to leave a long dot which does atonement healing.
To spice things up lets make Synergy also grant you a tiny amount of mana when you use it on a spell. To add more depth it could also be used to empower several different abilities, like PW:S to give out a huge absorb shield to the tank, or smite to give a strong pulse of atonement healing.
As a side note I also thought of another new ability.
Soul Heal: Instantly heals all targets with weakened soul debuff moderately.
Share your thoughts and ideas on this.