Hi @hcl,
Our motivation in removing those sections was to simplify the Setup areas (which were getting horrendously long) and simultaneously provide greater flexibility in presentation. This does potentially mean a little bit more caretaking in Setup when the roles change, but so far this seems to be a fair trade-off.
For migrating your existing journals, we may further automate the move of content from the OJS 2.x style into the OJS 3.x style – but until then one option would be to copy/paste the list from your old journal into the setting form in the new OJS 3.x installation.
Regards,
Alec Smecher
Public Knowledge Project Team