I think Green is actually secondary in Vigilance, because there are some recent commons with it (notably Sentinel Spider). Green is tertiary in Haste, though.

I think Hornet Sting and Leeching Bite are specifically against color pie. At least, from what I get from Mark Rosewater's dislike of Hornet Sting. I would assume Leeching Bite falls into a similar camp, since the previous iteration of its effect was Consume Strength.

I would wish for such an effect to cost only C, so the fact that it probably fits into multiple colors does not speak well for it ever actually happening. I was just curious since it seems like the key to making a "loses flying" card actually playable is to attach some kind of combat trick or removal value to it.