Two things here:
Hello,
For the first point, we'll open a ticket to make the change.
For point 2, you can go in File > Options > Path, and then click on "configure installation paths". In this list you can search for winbox, and there's a box to override the application executable. You should be able to put "winbox64.exe" there and RDM will use it instead of the default "winbox.exe". Can you confirm this works?
Regards,
Hubert Mireault