I would like to be able to use ed25519-sk keys. Right now only ed25519 keys and rsa keys seems to be supported.
Will it be possible to import -sk keys in an upcoming version?

You can file a feature request and you may get surprised by getting it done. Based on past experience (we were begging for anything besides RSA) it's likely to take a long while (so don't hold your breathe while waiting for it to happen).

Is there another way to post feature requests than in the forum? I saw something about a the Wiki, but that page is gone. By posting here I at least hope that someone sees it and adds it to some internal list.

I'm not sure what would be best feature request submission ... this forum is primarily users-to-users forum, MT staff occasionally pass by. So posting it here doesn't guarantee that it'll be seen by MT.

Higher probability of making it seen by at least some MT staffer would be submitting it via official support channels (e-mail of web page). These are primarily intended for trouble shooting / bug squashing / etc. though.

Occasionally @normis starts some poll about wanted new features ... and I think we (the users) have right to assume he'll check the thread from time to time. So you can wait for next such thread being open as well.

Mikrotik helpdesk. There is also an option to submit feature requests.

Wouldn't opening a bug/feature request be the best way?

Email support @ mikrotik.com

I found the feature request in the support login.
Here is their reply:

Hello,

Thank you for contacting MikroTik Support.

An ed25519-sk will not be supported at the moment.

We will note your request. If there are similar requests, we will consider implementing ed25519-sk key support.

Best regards,

Matīss O.