I think that I get your point. The wallet list are those wallets you have previously restored (The other question I did here: Cardano-wallet local-cluster empty wallets - #4 by Fivo89 highlight my misunderstanding about that).
If you hit POST /v2/wallets endpoint and the wallet already exist on the wallet “instance list” (is already loaded so to speak) it won’t return the wallet object BUT it’ll fail with an error message saying is already there, so if the list has more than one wallet how can I know which one is it?
I understand that from the point of view of interaction between users and the wallet server it’s ok this behavior since the user will hit the POST /v2/wallets endpoint and will end up with a list of wallets from where he’ll be able to recognize each wallet. But imagine that the interaction is between a program and the wallet server, the program won’t know which wallet is what and cannot pick accordingly (this could be the case of an exchange where the wallets are handle by the program and not through user interaction).
I think it’s kind of counter intuitive that the POST /v2/wallets endpoint doesn’t return the wallet if already exist.