The way you have the tag menu items set up, allowing us to filter by category is really fantastic. This lets us have links inside certain features to related items in specific categories. However there is no option to assign the template that will be used and thus, for me at least, this tag menu item is unusable because it will take the user out of the look of the section they are in and send them to a new template, which they will interpret as being unrelated to the section they are interested in.

An option to assign a template to the tag menu would be great.

Or alternatively to assign a template to a tag specifically, this might be easier.

And I agree with others that categories for tags are needed if you plan to use K2 to manage an entire site. Joomla sites tend to be more than just one feature and you don't want all of them mumbled together when people click the tag links.