Maybe instead of a ring of protection giving a +N deflection bonus, and magic armour giving an armour bonus, you'll just have one type. A ring of protection gives a +N magic bonus to all defenses, as does magic armour. So you can still have bling, it just won't stack. Therefore, there'll no longer be a reason for the Christmas-tree effect.
This is still slightly boring, but you could have other ancillary effects. Maybe it works M times/day, or only when something special happens (eg a sword that gives a bonus when you take down an enemy, or when you're down to 50% hp). Actually, I bet that some of these effects will be curses, just like magic items in the IH DMing guide.