I agree. Renew is almost usless at the moment. You can ditch more healing with other spells and the mana cost won't be that much different. Renew is a fail atm. Unlike rejuvenation spams. I find myself outbested in healing by druids in a few green items...But oh, well, nothing much has changed in terms of that. People keep telling me priest are epic in 25 mans...I do not do 25 mans and prob won't do in the next few months. If priests are good in there it's just because 24 people stand in the sanctuary...well that doesn't make us great healers, it makes our class abilities more viable, thats about it. I'm currently happy with holy priests overall, but we do need a buff. Those damn druids are still on top(on most fights) and those paladins mana regen is ridiculous.
As for the question.
Int(I get it from items and a few gems)>Spirit>Mastery>Haste>Crit - I get as much spirit I can and reforge what I can towards mastery. Mastery for holy priests is cool. I have like extra 26% of the amount healed and 26% is something.
P.S Gief holy priests more regen and a considerable renew buff, just don't make it the same as it was in Wotlk(spamming and such). And yes, I know Blizzard won't read this
. I just want to whine.