All development efforts are moved to Eclipse Babel. Do not despair as you will see the plugin resurface there, with even more features (it will now be called Messages Editor). There is no update site for the plugin yet, but the source should be available if you are comfortable enough with packaging it yourself.
If I understand you right, there is already a way to disable that feature. Look at the preferences for "ResourceBundle Editor/Formatting". There is an option called "At least one space each side of equal sign". That should do it.
