I think the new system sounds pretty good. I think it solved the major problem I saw in 3.0's magic item system, which was that +x items in a slot pretty much pushed everything else out of that slot. In 3.0 you would never wear, say, a hand of the mage because in almost every situation, an amulet of health, wisdom or natural armor was better.
In the 4th edition, they solved this by making it so that the +x items only occupy three slots, and that non +x items can't go in those slots (or rather, you get +3 of survival, like in the example.)
I never saw the "Christmas Tree Effect" as a big problem in 3rd edition, because to be honest, I was never totally clear what it was. It seems to me that it's more of a very loosely defined buzzword than an specific phenomenon. There's been like 4-5 competing definitions in this thread already, ranging from "PCs have an item in every slot", to "PCs need +X items to be viable" to just "magic items should be rarer and more special... Christmas Tree!"
I wouldn't mind magic items being more special but really it depends on the player. My main solution for more special magic items as a DM is to pay careful attention to the players and hand-pick items that I think they'll value, rather than rolling them randomly on a table, but that's not always possible. It doesn't work at all with pre-written adventures, for instance.
As for them being rarer, I've been using the Magic Item Compendium treasure tables, and am fairly satisfied with the way that works. But, if someone wants them rarer, it looks like you can just make them rarer without a big difference. The one thing I see a problem with is having a way so that each character doesn't have 6-ish secondary items by level 11, but the two solutions I can see there are either: give out less than 6 items per character (24 items in 110 encounters?) over 11 levels, which seems kind of stingy, but workable. The other way would be to allow the character to use less items, which would mean that the character would just have to min/max harder in deciding which items to keep, rather than the current way, where the characters actually keep marginally useful but interesting items.