The abilities and loyalty are pretty much just thrown on, but we mentioned having Gideon be the returning planeswalker for this set. I made this page to talk about him. I like the idea of him diversifying into another color, hence the cost I have here, but that's not to say I think he should go three color.
If I remember right, he became buddies with Chandra in the story (though I haven't read the book), so I thought about him being . However, that seems too close to Ajani Vengeant. I think we should do a new color combination.

This is a funny complication. My first response was "No. Gideon is White.", but that's not a condemnation of him being multicolor... it's more of a warning in the back of my mind that if we mess with Gideon's colors, then it better work.

If we are using Gideon as the Planeswalker du jour, are we keeping a similar plot with him, like I suggested when offering Gideon in the first place? Someone who comes to this plane, immediately sides with Aer because of his personal philosophies, then, as the conflict moves forward, starts to question his allegiance? If we do, then we may want to make Gideon Mono-White anyway... or White-Green maybe. A card like this may be more appropriate in the third set to show Gideon's change of personality through the block. Alternatively, we could put Gideon's card in the second set, at the moment of identity crisis. I like that idea, but something tells me it will be rejected :)

I'm fine with anything you've said. This is just here as a point of discussion. Personally, Gideon is pure white in my mind, and I have a hard time seeing him as another color. The only thing I think should be on this for sure is his last ability or some permutation of it.
I do think it would be nice, though, to have a three color planeswalker in the second or third set-- probably an ascended version of the wizard the started the crisis. Koth was a Mirrodin native; I think our plane should have a native, too.

It could be what got the normally passive races started up in the first place. A planeswalker appeared among their tribe, and the gods didn't seem so godly any more. Even more disconcerting, is that that planeswalker would be able to travel to the other continents, causing conflict, and pretty much mucking up this world.

I agree it feels like Gideon is the least likely of the white walkers to end up multicolour. Ajani already has done, and Elspeth is conflicted and Bant-affiliated. Gideon feels pure white to me.

But OTOH, I do like having a gold planeswalker turn into a flying creature. OTGH, a 6/6 invulnerable flyer is even more game-dominating than a 6/6 invulnerable non-flyer, so I fear this card may need to be about 6 mana; and if the creature gets smaller it'll draw unfavourable comparisons to the older Gideon.

I, too, very much like the 6/6 flying mode. That seems perfect for the set.

I also like that the planeswalker is gideon and that the cost is GWU (though I could see a variety of other combinations instead), although I agree we have to choose only one of those and not both.

Discussion of which planeswalker continued at: ~Planeswalker~