I think you're speaking in extremes. Bubble spam is good but very very mana intensive - I wouldn't suggest stacking pure Mastery, at least at this gear level, because you will still be using a lot of casted spells as a raid healer, and will be casting PW:S fairly often (and for a fair chunk of damage absorption) as a tank healer.
Crit is poopy unless you're primarily a tank healer. If you're a tank healer, reforge to crit and DEFINITELY get inspiration. If you aren't running smite spec, you should have enough points to get all the good talents in disc & inspiration. If you are running smite spec, spec out of it. :> Atonement healing is poop and the poopness is multiplied if you're supposed to tank heal.
For raid healing, the value of haste for disc priests has plummeted given the value of mastery. Since PW:S isn't affected by oogobs of haste like PoH is, we want more mastery than before (reforge crit -> mastery). If you aren't casting that many direct heals at all, then reforge your haste -> mastery as well. If you're still casting a fair amount of direct heals, the haste can be beneficial.
As for Inspiration with a raid healing spec, you should still get it assuming you do tank healing at any time ever(which you should, since shielding the tank & tossing him some spare penances is a great idea, especially if you have/get 4pc).