Miracle Cost:  

I probably don’t need to mention this, but [mtg_card]Terminus[/mtg_card] does cost W for the miracle cost: that’s one single white mana for a board clear. I know, I know, you have to draw it to get that effect, but believe me, you will draw it and cast it for it’s miracle cost more times than you think, even without four copies, which brings me to my second point…

You Don’t Have To Play Four Copies: 

A six-mana board clearing spell isn’t the most desirable thing in the present meta-game, primarily due to the strength of aggro decks, which dump their hand by turn four. That being said, you don’t have to run four copies. I mean, an argument could be made to run four, but ultimately you could run one or two copies and end up drawing it in your starting hand less often, thereby increasing the chance of casting it at miracle cost.

You can Cast it on Your Opponent’s Turn:

Chances are you are already running [mtg_card]Think Twice[/mtg_card]. By playing Think Twice on your opponent’s turn, you are allowing your self more opportunities to hit the miracle, increasing the value of the Terminus, and increasing the likelihood that you will actually cast it at Miracle speed.

It Doesn’t Destroy Creatures:

With [mtg_card]Voice of Resurgence[/mtg_card] increasing in usage, Terminus only increases in playability and value. Because all creatures go to the bottom of their owners’ deck, the Voice token won’t trigger, leaving you with a clear board and no pesky growing threat to worry about. I wish the same could be said for [mtg_card]Thragtusk[/mtg_card], but his effect still triggers, because he is leaving play.

It Wrecks Aggro Decks: 

In an environment where players are dumping five to six cards (counting land) by their second turn, Terminus’s value increases exponentially. Turn two or three Terminus for miracle cost against an opponent who has cast all but two cards in their hand will almost always win you the game. It quite literally WRECKS aggro decks, which is reason enough to play it.

Okay, so maybe I haven’t sold you on playing four copies, but if you’re playing a control deck with white, you should be running one minimum, with two also being a reasonably safe addition.  Pick it up and try it. It’s going for about one ticket on MTGO.