What color brings back planeswalkers?

I arrived at Red because I understand the flavor of planeswalkers as fleeing once they lose all of their loyalty. They're not actually dying. Red is the color of emotions, so can it manipulate feelings of loyalty and inspire the planeswalker to return?

Probably, though, the ability belongs in black or white.

Reminds me of One Last Favour. Maro says red can reanimate a planeswalker for a turn, but that's rather different.

There's something to be said for green... well, in fact, green can already get them back with Nature's Spiral (which is in the modern colour pie, TTBOMK, unlike Recollect).