Another observation...an almost assured chance at finding a magic item in EVERY locked and trapped chest?! I think that is...what's "more than generous"? 11% every locked/trapped chest is going to have magic items? Now, I'm ALL FOR high magic settings and characters dripping with magic items. So, if that's the style of campaign world you're working with, then fine. But I feel many other DMs here would find this 11% "chance" per chest to be very (too) high.
No, not in every locked and trapped chest. This is actually a fairly low magical item game. I allow them to roll on the magical loot table whenever I feel the players should receive a magical item. This may be after getting to the chest at the end of the trapped hallway, after sneaking into the mage's bedroom, or defeating the end boss of a dungeon. So when I want the players to get a magical item, they have an equal chance of getting a level 5 item as they do a random potion (the random potion being a booby prize).
Given the feedback you've received from your players and that they enjoy it (the delusion that they hae some "control" over a die roll) then "Good DM" points for you for engaging and making your players enjoy themselves at your game. I will certainly give you kudos for that even though this "system" is not something I would opt to use myself.
Thank you!
And on a "simply curious" note...why when generating the decks with all of the magic items for "arms, hands, feet, etc..." did you NOT include rings?
Seems to me rings, especially in a "high occasion of magic items world" would be a very common find! So, I'm just wondering your thought process for excluding them.
This is a good question, and the answer is specific to 4e: in 4e, magical rings are supposed to be extremely rare for some reason. In fact, the lowest level magical ring in the Adventurer's Vault is at level 14. I'm not sure why magical rings are rare and magical hats, shoes, etc. are much, much more common. Seems a bit odd to me too.

PS: And don't sweat the lack of responses. Sometimes people have stuff to say (in abundance) and sometimes they just don't. My thread on the "Plots and Places" board, Orea: The World & Its People currently has 987 views...and has garndered not a single comment to any of the content...other than someone I'd never seen on here before telling me "thank you" and subsequently deleting the post, so I think it was a mistake.
Maybe I'm too used to geeks who like to talk and argue.

-Dave