Wheels are strong. Being able to wheel every turn is potentially game breaking. There are enough ways to cheat on equip costs, but, yeah, in general, it's a neat concept. If you want to make it a little more fair, you could have it draw equal to the most a player discarded (a la
Windfall), or have it cost something to get the effect (when creature deals damage, you may pay 2/sacrifice an artifact/whatever cost you like. If you do, each player discards...). I personally prefer the more restricted triggered ability over the more restrictive cost. It's easy to cheat something into play or onto a creature. It's a lot harder to cheat activation costs.