>>16713908Yeah, but in this case it is a gimmick already written into the family by default.
I tried to come up with an analogy for a circle of useless and overlooked pokemon around the one that will always be used, but found nothing and went with the first thought that came along, sorry.
What I tried to argue was that such concept as
>>16713188 has outlined wouldn't have used its potential as a tag-along. Such potential would work best as a fresh family built around such gimmick.
There is also a question of how often such hypothetical third player at Ralts family would be used. Gallade is already a weak, useless pokemon that fell out of popular scene - I don't think that such a newcomer would fare better - at least not without a BST spread independent from Gardevoir's.