You can have as many Cids in your deck as you like, but only one on the battlefield at a time - as he is a legendary creature
The problem was that mana back then was nowhere near as generous in Standard, and in Extended where the Sliver decks came into their own they mostly proved too fast for the big old Queen even though the mana could usually handle it
At the same time, an expensive Commander is a guaranteed late-game threat
In terms of power loss this list looks fine, it looks like it has a pretty high average power level of cards that operate suitably well together with a nice range of effects and options
those other effects can also be very efficient, but to narrow things down, this article will deals with effects that destroy or exile a single target
Storm the Vault // Vault of Catlacan is one of the least playable cards I have seen in some time and another consequence of the devastation caused by Academy