Maybe I've seen them and maybe I haven't. Whether or not I've seen fourth edition items, however, I think that historical and an argument from general principle is sufficient to demonstrate that non numerical bonus items will have an impact on power. Consider the following principles:
Magic items are either useful or not.
If the items are useful, then they increase PCs' power.
If the items are not useful, then PCs will sell them and buy items that are useful.
If 4th edition DMG non-bonus magic items are all of the kind that you suggest--you can keep (or buy or create--remember that item creation is supposedly ritual based in 4e, not removed entirely) a magic item in order to do 2d6 damage instead of 3d6 damage with your eldritch blast, then nobody will buy them, nobody will make them, and those who find them will sell them in order to buy better flat-bonus magic items. And within a year, WotC will put out a book with magic items that are actually useful and that people might actually want.
However, history suggests several things:
1. There will be a mixture of power increasing, power reducing, and combat irrelevant magic items in 4e.
2. People will buy, create, and keep the power increasing magic items.
3. People will sell or not bother with the power decreasing magic items.
4. People may decide to splurge from time to time on combat irrelevant items--as long as they're cheap or have clear uses.
That is how it was in 3rd edition. If you did a survey of any decent sized group of gamers, I suspect that you would find plenty of 3rd edition fighter type characters who had +1 flaming, +1 frost, +1 shock, +1 wounding, and most especially +1 holy weapons. You will find very few who bothered with brilliant energy weapons. Likewise, you will find that a very few characters bothered to aquire rods of wonder, but all sorts of characters gravitated to strands of prayer beads, metamagic rods of quicken, empower, maximize, and extend spell. The same with shields. Any survey of mid to level armored characters would find all sorts of animated shields. It would find very very few blinding shields. What's the common denominator in all this? Players gravitated towards the power increasing items and largely ignored the power decreasing items (like the blinding shield).
For that matter, that's the way it worked in 1st and 2nd editions as well. You saw all sorts of longsword wielding characters, dual wielding characters, and bladesingers because those were the most powerful options. In first edition most fighters ended up wearing plate mail--or maybe field plate if it was available--because that was the best armor out there.
Now, as for the 4th edition items article. Two things. First, I wouldn't believe everything the designers write in those articles. That's marketing material from people whose future income depends upon generating buzz and excitement about the new product while simultaneously degrading and diminishing the old product. I'm sure they're mostly decent people, but the need to put food on the table has a big influence on most people.
Second, I don't think you read the same article that I did. Yes, one of their goals is to make characters abilities more a function of their class than their items, but they also said criticized items that "weren't as exciting as magic items should be." How exciting is a ring that does 2d6 fire damage for a character who can do 3d6 eldritch blasts without it? But that's marketing fluff. (Complete with criticizing 3rd edition--if you don't have something bad to say about 3rd edition, don't bother writing seems to be the rule for these preview articles, much like if you don't have something good to say about 4th edition, don't say it is their rule for playtesters). Where they give us a real preview of what we can expect from 4th edition magic items is in the description of items slots: Arm slot items give special defensive effects (shields) or are more offensive. Feet are focused on mobility and special movement modes. Hands help out your attacks or your manual dexterity. Head items increase your mental skills or senses. Waist items are usually about protection, healing, or temporarily increasing your strength. If you ask me, "helping your attacks", "special defensive effects", "increasing your senses", giving special movement modes, and "increasing your strength temporarily" all sound like they would be designed to be useful in combat.
What may be even more relevant to the discussion: The list of items for the 11th level gnome warlock:
Bracers of the perfect shot. Sounds pretty combative to me. Belt of Battle. (Hmm. Maybe WotC actually thinks it's balanced).
Now, comparing the list of magic items is also interesting from if you think that 3rd edition characters positively drip with magic items but 4th edition characters won't. The character is 11th level, which probably is equivalent to something between 7th and 10th level in 3.x. 7th is where it would be if you evaluate the percentage of levels left to go in the base ruleset. And, 7th is right around where the first real transition happens in 3rd edition D&D (as evidenced by the epic 6 movement). So, +3 rod of dark reward, +3 leather armor, +2 cloak of survival, bracers of the perfect shot, wavestrider boots, shadowfell gloves, diadem of acuity, belt of battle, and a bag of holding is 4th edition magic. Curiously, my 7th level paladin who died in age of worms had: +1 returning trident, +1 fullplate, +2 cloak of charism, +1 vest of resistance, boots of striding and springing when he died. So the 4th edition character has nearly double the number of magic items that my (not too unusual) 3rd edition character had. How about the 8th level fighter/scout who replaced him? +2 gloves of dex, +1 frost greatsword, +1 mithral chain shirt, +2 vest of resistance. About the same ratio. Now, in 3.x, that amount of magic seems to take off around 11th-13th level, but at the only data point we have, the 4th edition character seems to have twice as much magic as the 3rd edition character at the equivalent point on the progression.
Hella_Tellah said:
He says without ever seeing 4th edition magic items. Consider this: a hypothetical warlock can use an eldritch blast at will and deal 3d6 damage at the cost of a standard action. He then gets a magic item that allows him to produce a blast of fire that deals 2d6 damage as a standard action. Now, if that 2d6 fire damage item's level is the same as the level at which the warlock's eldritch blast improves to 3d6, he's exactly as powerful as he was before, numerically. He just has the option of using fire instead, and it's not even optimal in most situations. He's a little more effective against white dragons, but not so much that you'll need to completely scrap the CR system.
It's really easy to dream up magic items that don't have a strong net effect on character power; they just need a suitable drawback. Luckily, having an item cost an action is a perfectly scaled drawback, because the item has opportunity cost built in. The character can either use a standard-action power, or she can use the item, and if the item is a little bit weaker than a standard-action power, it won't have a strong impact on balance.
The items you referenced above weren't designed to be power neutral; they were designed to compete with other magic items commonly used in those slots at those prices. They were designed for 3rd edition, a game in which all magic items are expected to increase character power, and in which all characters are expected to absolutely drip with magic items. We have no reason to think 4th edition magic items will be anything like that. In fact, the
preview article we saw suggests the opposite.
