Charged Magic Items

I just read this blog post on Dungeon's Master, and I must admit that it intrigued me.  I'm seriously considering implementing this as a house rule in both 4E and 13th Age, both systems which lack a charged magic item mechanic.  Though some modern games (like the aforementioned two) have done away with them, I think that charged magic items hit a sweet spot in magic item design. 

Consider two extremes in design; the do-anything magic item system of 3rd edition D&D vs the bland system of 4th.  In the first case magic items are arguably too easy to acquire and too powerful (for parties decked out with a lot of them), and in the other they simply weren't interesting even if they remained easy to acquire.  Having charged items as one element of the magic system was something that 3rd edition did right, though. 

I'm specifically thinking of a middle ground here.  A system where PCs are not dependent on keeping a suite of magic weapons, implements, armors, etc up-to-date just to maintain baseline competency, but with items being interesting enough to feel "magical."  They should be rare, tough or impossible for PCs to create themselves, and should have certain limitations or drawbacks depending on the item's specific power level.  Charges are perfect for this!  More powerful items have fewer charges, less powerful items have more.  Some items might require a skill check to activate, while others would be more widely useable.  Best of all, a flexible system that gives GMs plenty of guidelines (trial and error is fine too, if you're house-ruling) would foster the creation of custom items.  Theoretically, any game element (a maneuver, spell, monster's power, etc.) could be replicated as limited-use magic, with the GM tweaking skill check requirements, number of charges, and recharge rolls to account for how s/he envisions the item impacting the party dynamics.

Besides which, deciding how/when to expend charges gives the PCs some interesting resource-management decisions outside of any full rest/daily mechanic that may be present in the system.