Part of the three word mythic rare cycle started with Evanesce. It's kind of goofy, but of all the cards of this cycle, this is the one that excited people when they drafted it. Nine is strangely both too expensive, and too cheap for this effect. Life gain is strange like that.

Oh, also, I might have been thinking of Logan's Run when I named this card. :)

­Heroes Remembered says 9 is good, but it could probably cost 8. Also, that straight up lifegain this efficient and powerful is probably white. And also that this probably doesn't need to be mythic.

I forgot about heroes remembered. Dropping to 8.

It probably doesn't need to be mythic, but what does need to be mythic. I understand that cards , like Emrakul, the Aeons Torn, with absurd costs and abilities scream mythic, and that planeswalkers are by default (this set's planeswalkers are coming). After that, though, the distinction between mythic and rare is "Is it splashy enough?" Wizards thought Serra Avatar, Thundermaw Hellkite, Vampire Nocturnus, Sublime Archangel and Primordial Hydra were all splashy enough for mythic rarity in Magic 2013. Many of those cards don't need to be mythic to me either... but there needs to be some cards in mythic that aren't goofy, overpowered or hackable, and those fit the bill.

Had this not been part of a three-word-mythic-rare-cycle, then I'd have no problem moving into the rare slot. But it is, and there just aren't many three word combinations out there... dropping this card roughly drops the whole cycle, and I like the cycle as a whole, while I have problems with individual parts. I could always scale the dial up... but gaining 20 seems like the best number to me.

As for whether this ability is white... that's an interesting argument. Personally, I've always associated gaining lots of life with green, and incremental life gain with white. But you're right that there is the occasional white card that goes nuts, gaining you a gigantic pile of life. I don't know if that means green can't do it... I'd think about switching to white, but, again, Evanesce.

This fits into the Alpha approach to lifegain. White gets Healing Salve; green gets Stream of Life. Fine by me. I also think this is viable for mythic.