Hi,
Thank you for asking.
I understand that your requirements are genuine and will be useful for many It may not be something I plan to add in this plugin.
The current plugin simply makes the main sites all terms available to other sites. That is simple and efficient( not the best solution for many scenarios though ).
If we want to move per taxonomy terms, there are several factors to consider. The most important is synchronization on add, delete as we will need to propagate terms from any sub site to all other subsite and depending on the main network size, this may not be efficient. Specifically, for larger networks, that will make this plugin useless.
This is the reason, I have avoided this feature. Sorry for not being able to help much here.
