With RC1 we had a complete feature freeze, so nothing that is not a bugfix gets into SVN anymore until we release the final version. Especially renaming tables is not possible during feature freeze. To rename the tables we would have to expand the installer first and add conditional code that repairs the installations after the table changes. There are already several thousand installations of ISPConfig 3 out there and I know several which are production systems, so we can not even break the compatibility between RC1 and Final.
I really like your plugin but it can be integrated first after the final release.