Doing my part to keep the new gripes thread free from excess clutter,
this post brings me to this piece of content I'd love to see.
I'd love to get a piece of offhand equipment to act as a spell book rather literally. When equipped, it could allow you to take one or two extra powers into combat with further limitations. One could be limited to only non-stance at-will powers, and the other could be either a recharge power limited to once per encounter or an encounter power limited to once per rest like an ultimate. They'd be limited to only pure spell powers, so you couldn't bring in say, fan of blades or something like that.
I realize it wouldn't be the most feasible thing from a technical standpoint but it would be very nice as a mage to have a few more options, and it soft-balances by not allowing two-handed weapons or other offhand, stat-giving gear.