Black loves to spend its life on other luxuries and so having worthy cards that can replenish the life total are of much higher value that they are in other colours
That exile effect is enough to make it worthwhile, but Daretti and Goblin Welder allow you to reuse it whenever a player starts rebuilding their graveyard
Its very easy to fill your deck with scry effects in blue, and many Simic elves in this set have a scry theme
But another player managed to get a very good score with some clever disruption: Turns out, while we changed the rules so that the next time Strip Mine gets run, it will be banned for the following round--but nobody actually played Strip Mine in round 4
Recently, we've seen Wizards take change the actual rule that affects the card (like the companion mechanic) instead of tampering with individual cards
Similarly, in my Top Ten List, Ephara, God of the Polis, which is a pretty good card, hit #10, but no higher