I'm glad a lot of you are interested in these alternate Pokemon! Metallic imo might be most likely given that it could keep the shapes and outlines of the Pokemon and just... make it different. I also like how people suggested crystal Pokemon (iirc?), because that'd definitely be an amazing thing to find. I mean ever since the crystal Onix episode I don't see why they can't just do that in the games. If we were to find those in the games I would love it a lot <3
I have to say I like this idea. Things in nature have genetic mutations and shinyness may be partially based on this itself, but I wouldnt mind seeing more along that line. Things that make them different than their normal counterparts. I like the shadow/metallic idea or maybe just making a mechanic where certain ones have a different appearance. I wouldnt mind an additional shiny pallet as well, perhaps making one rarer then the other or the same, it would be fun to run into more colors of a single Pokemon, but maybe make them rare again like they once were in some way.
I think I used to play a game along the lines of that except instead they had ancient, mystical and dark Pokemon. Essentially ancient Pokemon had a higher defense then usual, while mystical Pokemon had a higher evasion rate and dark Pokemon with stronger power. I like the idea of alternate shinies, that would be an interesting feature to see. :3
I don't see what the point in adding something like this would be. Would it have any merit over just being another alternate appearance? If yes, I think it would be a cool idea depending on how it played out. If it's just another aesthetic difference, shinies are already enough in my opinion. Adding new versions of Pokémon just for the sake of aesthetics doesn't really seem to be a good reason to do something =/