Whenever I import from my SMF2 installation, it works without issue, all of the users are there, their passwords work, the roles come across...but no user is assigned a role.
Am I doing something wrong?
I don't know if you are doing something wrong or if program is doing something wrong.
but you can easily assign roles via phpmyadmin in the usertole table. Each userid has a roleid number that matches a roleid in the role table and permissions table.
Conversions frequently don't match the standard roles and numbers and its probably worth it matching them in the long run, if you have the time
there are other discussions relating to roles and permissions that can give you insights.
I may not provide the completed solution you might desire, but I do try to provide honest suggestions to help you solve your issue.