Check out the most recent weekly Marmot:
The next one will go into more detail on specific point-based loot systems.
My recommendation would be EP/GP, as it's a good balance between fair loot distribution and upkeep. While you could prioritize healers over other casters just by asking healers to declare first and only asking for further declarations if none of them wanted it, I wouldn't recommend it.
If you want to distribute loot purely for progression (and really, unless you're pushing for server firsts you probably don't need to), then you want loot council. Mixing class and role prioritization into a point-based system is just going to tick people off.
Healers and Tanks do not carry the entire raid on their shoulders, at least not to the extent that they did in earlier expansions. Your best geared healers and tanks can't beat an enrage timer if you've kept gear from your DPS.