-X% Cooldown items
So, one of the very weirdestly balanced effects in the game, is the one that decreases the cooldown cost of all your abilities. You can see it to a large degree on a couple favor items, and a decent degree from Sedna's Magnificent presence, heck even from Flags. But you don't ever really see it in moderate amounts for low to middle tier items.
I think this is a mistake, a fairly noticeable one the further into the game you play, and is part of the reason you see end games dominated by basic attacks. If sedna can heal 630 hit points between your 1350 damage fireballs, and get a priest heal, you aren't making much progress... AND can't increase the damage!
There is currently exactly one item in the game, that is purchaseable that decreases cooldowns. I'd like to see more, and then have a few of the other effects (names the Assassin item, and the flag) decreased in effect. Let a caster DG pick up -10% and -5% items to stack a fair number of them together. Cap it, just like we do with attack speed increases, and I think we'll add some interesting depth to the game.