I like the new enhancement system and how it lets you get access to high-tier skills early on, if you're willing to devote all your APs towards them, and then build outward from there as you level up and get more AP to play with, more flexibility as you level up.
Contrast that with the gear system, where every piece of gear has a hard minimum level, directly related to the enchantment level on an item (2n-1, IIRC). There is no tradeoff involved there, you either are minimum level or not. Your choice for each slot has no bearing on your choice for any other slot.
I'd like to see the equipment system change to a maximum TOTAL of Enchantment Bonus for the sum of all your gear. So if you're L7, instead of being able to equip a piece of gear with an Enchantment Bonus of 4 or less in each slot, you'd have 12*4=48 total Equipment Points to spend, for your 12 slots. If you wanted to equip a really high-level weapon, you could, but then you couldn't equip a good armor, ring, trinket, etc.
A couple small changes, of course, would be necessary:
-The few quivers with MLs would likely have to be manually rebalanced, so that ranged chars didn't have an extra slot to spend Equipment Points on than melees
-TWF/S&B/Weapon and Runearm combat would only count whichever is the highest of your two slots, to keep it equitable with THF.
-Specific named gear may still have a hard-coded minimum level, and Epic gear may still require 20.
I think this would have a number of good effects on itemization:
-It reduces the number of "twink steps" for TRing. You could equip a Greensteel weapon at L1, though you'd be pretty much naked except for that.
-Lets you have a more fluid transition between early-game/Heroic, when offense is all you want, and late-game/Epic, when you need more resists and defense and DCs.
-More economic interaction between high-level characters (most of the population; they get the best drops) and low-level characters (who currently don't usually have much selection on the AH).
-Item effects that are currently underpowered or even pointless at-level might be useful or even desirable at lower levels.
-"Cheaper" versions of things might still be desirable (ie, EN/EH versions instead of EE versions) if it lets you equip better things in another slot.
-Items that stay useful for many levels (ie, GH/Dragonscale Armor, Cannith Challenge gear) will give you some additional benefit - meaning future updates don't necessarily lead to the mass rush to replace all your old shinies with the new shinies.