FireLance
Legend
I believe that in a manner not unlike the "what the customer wanted" swing cartoons, the "PC progression math" of 4e started out with a rather simple objective that gradually got more and more complicated.Either way, with items or without you are still on a bonus treadmill and have to keep up in order to be of any use. How bout ditching the need for tons of tems OR 'just because' bonuses and reducing overall numbers bloat?
The first, rather simple idea: To make adjusting monsters on the fly easy for the DM, increasing a monster by one level should increase its attack bonus and AC and other defenses by 1, and its hp by a number (6 to 10) according to its role.
Step two: This creates a 29-point difference between a 1st-level monster and a 30th-level monster. In order for the PCs to keep up, they need to gain about +29 to attack rolls and AC and other defenses between 1st to 30th level.
Step three: Level-based increases should take care of some of the difference. We'll go with a rather simple 1 point per 2 levels, instead of a more complicated formula like 2 per 3 levels or 3 per 4 levels. That takes care of 15 points, leaving us with 14.
Step four: Ability score increases would further close the gap. 3e gave +1 to an ability score once every 4 levels. To make it easier for the players to remember, we'll give out a +1 to two ability scores at every level ending with "4" or "8", and at the start of the Paragon and Epic tiers. That makes +8 to two ability scores, which accounts for another 4 points, leaving 10.
Step five: Traditionally, we also have enhancement bonuses from magic items. Since they can now go up to +6, that leaves just 4 points. We'll have a variety of methods to close the final 4 points: some feats, some item bonuses, some powers, etc. Most players would have one or two of these, and even if they don't, a four-point gap probably shouldn't be crippling.
So you see, if they were willing to use more complicated formulae for monster math or PC level-based increases, we wouldn't "need" magic items to balance the math: a 2/3 progression (+20 over 30 levels) would reduce the "required" bonus from magic items from +6 to +1, and a 3/4 progression (+22 over 30 levels) would eliminate it entirely.