I think the new system has really given DMs a way to play lower magic worlds or greater magic worlds without unbalancing the campaign in a way 3e did not.
If the expectations are for 3 slots to be close to X at certain points for balance and the rest are merely flavor, then it is easy enough to have
a) a low magic campaign that doesn't restrict the "neck" powers to the neck, so that characters can have the require primary powers in different slots, and only have 3 or 4 items throughout their career, which the article states won't be unbalanced against the players.
b) a high magic campaign with lots of treasure all over the place, magic markets in every town, and huge hoards of loot in every dingeon. Since only 3 are the prime power slots, so long as those are appropriately balanced to the level, characters having lots of options for every other slot won't unbalance the game. Magic items are so optional that they are not even needed, then conversely, they aren't powerful enough to completely unend a game if the player is given a wide range of options.
The 3e philosophy: you need 8-12 magic items of respectible potency to succeed at higher level play, and you will be constantly upgrading old gear for new, better stuff to in order to survive.
The 4e philosophy: so long as you have these 3 items at the appropriate power levels, you are fine and balanced. Everything else is up to how the DM wants to play his campaign world.