I would suggest this as a template for the rest of the abilities, for the fact that some of them are near misses of abilities already present - Harvest is remarkably close to Dredge, par example. I also really like the idea of making a series of cards which reward you just for performing on-color game actions in some measurable way - especially if those game actions are 'primary' by definition but 'secondary' by nature of the game. Life gain is a great example; it's widely regarded as barely playable unless in cascades, and even then it is useless in certain matchups (many combo decks do not care what your life total is, they will deck you or kill you for 2^64 damage anyway). Make a deck which rewards *itself* for life gain, and suddenly that secondary effect of White becomes an engine for Good Stuff. There's lots of effects like this throughout all the colors; Red's penchant for randomness, Blue's deck 'rearranging', we could go on...
This is actually what I'm trying to accomplish. Blue is rewarded for controlling the order of its library; Black is rewarded for having a big graveyard; White for gaining life, Red for going all-in and casting alot of spells, and Green for having creatures (greens is the one I like the least right now, actually). I agree that Harvest in particular is awfully close to Delve (I think you meant Delve not Dredge). I sorta like the Blue and Red ones though. I dunno, what do you suggest for Black?
I've got other bigger points to make, but have been purposely holding off until this in particular gets talked out one way or another.
From my perspective, you started a meta-argument a few posts back about who said what when in order to be Moar Right. I think, at that point, the conversation is pretty much done. I’d rather argue about something than argue about arguing about something!
The nearest to resolution is something like: A creature that gets bigger equal to the life you gain has a useful ability that, like all abilities, must be balanced in some way. We didn’t need quite so many words as we used to get there.