Recently, I've had a rare need to check interwiki links. I've discovered
that many times, the universal login credentials are not working.
For example, after login to english, the french link seems to accept the
credentials (most of the time), while the german link *never* accepts the
credentials.
Moreover, there is still the problem with secure, in that following
interwiki links doesn't stay with secure, so have to re-login for
each site. (Also, secure is slower than ever, and edits sometimes log
the IP instead of the user name.)