From the Article:"Second, characters cannot normally create or buy rare items. They are simply too hard to find to show up in the hands of a merchant or trader. You must find them or, at the DM’s option, track down the rare and wondrous reagents needed to create one. You can’t simply stock up on them or buy one for each item slot."
This is /exactly/ how all magic items (other than potions and scrolls) worked in 1e. Everyone remember how /wonderfully well-balanced/ magic items were in 1e? How they never caused any trouble? No? Me neither.
There's a hard guideline for giving out rare items - 1 per character per tier. That's not a bad guideline. It's still a guideline, though, leaving the DM plenty of room to screw up by giving too many or too-powerful rare items out. And, afterall, part of the point of rare items is that they won't be carefully balanced, they'll be quite potent for their 'level.'
There is only a soft "less than half the items found" guideline for uncommon items. More room for the DM to mess up.
Common items are basically a slot tax, you need to get those Enhancement bonuses to stay on the 4e treadmill, since the monsters and challenges get harder every level, but you only get better every other level. Flip the damn 'inherent bonuses' switch and be done with it.
One truism with 1e was that characters - particularly the non-casters - were defined primarily by their magic items. Stats were just bland numbers, and there was virtually no customization or choice within a class. You were your items. Some folks liked that, many objected strongly to it.
The 'feedback' the article says they've been gettting about items starting to overshadow character choices would seem to echo that ancient complaint. Players want their character to be special and defining (in ways they choose), not their character's sword to be special and defining (in ways chosen by the DM).
Yet, that's exactly what rare items are likely to do.
Then there's uncommon items. They're mostly dailies. They'll account for something less than half the items you find, so, you'll still have quite a few item dailies available as you go up in levels.
One of the complaints mentioned in the article was: "Particularly at high levels, a character’s boots, armor, gloves, belt, weapon, and other gear add quite a few powers and abilities that might overshadow other character aspects."
So, having too many items dailies was a problem. The solution: scrap the limit on item dailies. ???
Characters will still have multiple item dailies. There'll be less effort to assure that they're balanced and don't overshadow character abilities - that responsibility is being pushed on the DM. Characters will get to use /all/ their item dailies, every day. So, they're not likely sell an item with a daily - it might come in handy, and it's always available.
Once again, the line from WotC about Essentials isn't quite making sense. If the idea was to keep items from overshadowing PC abilities, you wouldn't add in even more-powerful items. If the idea is to limit the use of many item dailies, you wouldn't lift a restriction on item dailies.
If the idea is to make the game feel more like older editions, when items could rarely if ever be bought or sold, needed bizarre rare materials to make, and could be arbitrarily powerful and character-defining, all giving the DM a major headache when it came to maintaining balance within his party, OTOH....