Before I really start complaining, though, lets look at some numbers.
The mana cost of penance: 3294
The cost of penance as a percent of base mana: 14%
Base priest mana at level 85: 23528
Stats on crafted pants: 341 int, 228 to two ratings
Total stats from a full set of gear excluding trinkets: 3403 int, 4550 in ratings/spirit
Trinkets: 197 int, an on use ability for 500 int, and we'll guess our other trinket can give the equivalent of 197 to two ratings
Guesstimated base int for level 85 priest (really a guess): 220
Stats from known enchants: 100 mastery, 65 haste/crit, 20 all stats, 110 int, 40 spell power, 30 spirit
Raid buffs that will affect int: Kings, Flask: 300 int, Food: (estimate) 60 int
Final int (presumed for now to equal spell power): 4740
Arcane int: 5401 mana
Total mana: 100,029
Guesses on scaling:
Tiers of gear: 4 (plus one phantom tier for heroic modes)
Levels per tier: 13
Level increase from tier 1 to tier 4 heroic: 52
Stat increase from 52 levels: 63%2
Lastly, we can include talents and abilities. Inner Fire is 1080 spell power at level 85, and presumably we will talent for improved inner fire since it doesn't look like we'll have anything else to put the points into, so that 1566 more spell power. We get 6% more maximum mana from enlightenment.
So, finally, here are the stats I'll use to look at how the cataclysm numbers will shake out for priests:
|Raid Tier 1||Final Raid Tier|
1. Whining at WoW developers should always be in the form of constructive arguments if you want your whining to have any useful effect. E.g., "I think that your current criticisms of the twitch-reflex world of limitless mana healing are excessive in their downplaying of the skill involved and make it seem like people don't make choices because it doesn't matter much what they do. While I agree with going in the direction making mana matter, and I find healing low level dungeons where mana does matter to be more fun than the current high-level healing environment, you have to realize that people make the choices they do for very good reasons: it is because certain spells are much more powerful than others. If a spell is instant cast, is efficient and has very high healing per cast time, then people are going to cast that spell exclusively whether mana is a consideration or not. Rejuvenation and Power Word: Shield are both examples of this... WAAAHHH!"
2. In reality gear inflation is more than this because the first tier has zero or one gem socket and the last tier has two or three, which increases the numbers beyond iLevel increase. Probably a couple extra percent, and a very stupid couple of percent at that.