Just because you can run out of mana in 20 seconds doesn't mean you should do so. Nor does content require that you do so, whether it be normal modes or 5-man heroics or raid content.
A lot of people seem to be confusing the lvl85 Cataclysm healing environment with the following factors:
-Everyone being undergeared. Full ilvl333 is what heroics were tested with on beta, not half quest greens and blues. That gear makes a HUGE difference now relative to WotLK and prior, where gear did not scale anywhere near as sharply from 70. Unless you're a skilled player running with other unusually skilled players, you should probably follow that ilvl329 recommendation for heroics (without cheating the system).
-The average player re-adjusting to new content. Fresh 85 dps should be doing far more than the 3k dps I've seen in many random PUGs. Fights will be drastically more difficult if you're effectively down 1-2 dps for 5-man encounters. This is partially due to the reason above.
-A different progression path. You're meant to take advantage of all those nice rep vendor blues that are earned simply by questing. You're also meant to run normal modes before heroic modes for appropriate gear. I've seen far too many PUGs ignore both of these.
-Individual class balance. Yes, druids are weak right now. Yes, paladins are strong right now. No, this is not the reason that you're struggling in heroic content. Yes, the 85 healing environment is more enjoyable when you have tools to handle all situations.
-The fact that Cataclysm encounters are longer. Raid encounters often take 6-8+ minutes and 5-man encounters don't end within a minute (WotLK heroics on day1). Even if you were burning through mana fast in entry-level heroic WotLK content in entry-level gear, the fight would be over before OOM.
-Pre-tuning beta content. It still feels like some people are going off of the feedback given by beta testers (like me), which was used to fix much of what was wrong with the Cata healing environment a month or two before live.
I really can't think of why people would dislike the Cata 85 healing environment itself unless they were content to faceroll 5-man WotLK content all the time or preferred button mashing fps-like raid environments. The 85 healing environment has allowed for a LOT more potential difficulty and interesting healing mechanics in the raids I've seen so far, and it has done the same in 5-man content. And in 5-mans, it actually makes dps into a non-faceroll role in PUGs.