What feature do you want to see added?

I know this likely not to be widely used, but I would love to see support for LDAP(S) as an authentication module. I have a FreeIPA server setup to help with SSO for my community, and making it to where my community can use their existing username and password would be so much nicer.

Are there any alternatives?

It's a bit niche, so no.

Anything else?

I'd be willing to put up a bounty for this functionality if there is enough interest.

+1 for LDAP authentication, would love to see this feature added