I have to believe this has a place somewhere in vintage. The effects are all very good, you only need to emblem once a game for free and then all subsequent Gideons are platinum angels, he can be cast of a lotus T1 to prevent getting blown out but storm combos potentially, and walkers are still hard to deal with for some lists.
Maybe a sideboard card is more likely the place for it, but it seems unique enough that it could steal some games from players who are unaware.