Problem one exists because, apparently, MITM is a problem with TLS because it's possible for bogus certificates to get through? Well... I guess. But then that's

Problem one exists because, apparently, MITM is a problem with TLS because it's possible for bogus certificates to get through? Well... I guess. But then that's a TLS problem. And your entire banking website is served through TLS. So, if it really is an issue, then solving it just for auth is like putting an Abus padlock on a screen door. Problem two bemoans the bearer token in Oauth 2. Yes, it's not as secure as OAuth 1, but it's also far simpler. But you don't have to use bearer tokens; you are free to use MAC tokens instead. Why reinvent the wheel?