These items are set to disappear when the Love is in the Air event ends.
Easier itemization in Cataclysm (Source Re: Cata changes with itemization.)
We aren't trying to kill spreadsheets or simulators, and I'm not even sure we could. The situations where two pieces have different stats but provide an equal dps increase are always going to be rare.
The problem we're actually trying to solve is where one stat is so far superior to other stats that the rest of the item is irrelevant. Currently, most casters prefer haste over crit to the extent where they might use an item from a previous tier. That's not ideal (though obviously something else could be going on with their decision, like they are passing to someone else to be nice or they have a better upgrade in mind on the next boss or whatever). In Cataclysm, given an item with haste versus one with crit your spreadsheet might still tell you the haste item will provide more of an upgrade. But hopefully it won't be such an upgrade that the decision becomes a no-brainer. Hopefully the other stats on the item will come into play more. It's too easy currently to focus on The Best Stat to the exclusion of all else. (I'm not talking about stats such as spell power, attack power or Strength, because for most of your pieces, those just scale with item level. I'm talking about the secondary stats where the real gearing decisions come from.)
Overhealing and mana pools in Cataclysm (Source Re: Cata changes with itemization.)
That's a relative softball question, because the problem is healers overheal by so much now *and* can get away with it. If you actually care about your mana pool, then regen (Spirit in Cataclysm) matters. If you actually care about mana, then getting bigger heals (such as getting crits) matters too.
Now imagine that as a druid, your mastery stat does something interesting to your hots. It has to be *interesting* or it's just going to mimic the effects of spell power (Int in Cataclysm). Let's say mastery increased the duration of your Rejuv, but did so without reducing the healing per tick. Now Mastery helps throughput, but doesn't help burst healing as much as crit. If haste also affects how often your hots tick, then you might get some interesting gameplay out of playing off of longer hots that tick more frequently. If you don't need to spam heals as much as you do today, then reducing cast time through haste isn't as important to a healer, though it still might be desirable. Now you can make interesting (we hope) choices about whether you want more crit, more haste, more mastery or more spirit.
Itemization and power growth (Source Re: This is why the game is gettin out of han)
Yeah, exponential power growth is just part of the design. It doesn't really bother us that the delta between character level and item level keeps growing. It might be a problem someday if it takes scientific notation to express how much Agility there is on your breastplate.
The problem folks are referring to for this expansion is that we based combat ratings, especially things like crit and hit, off of one assumption for what gear would look like in 4.3, but adding the hard modes meant that the gear ended up having more stats than we thought. If we ended up squeezing in additional tiers into Cataclysm the same thing would happen, though we also have some ideas to make the scaling work better in general.