In course/lib.php (around the line 3760) we have a hard coded value of "5" for the number of courses displayed belonging to a certain tag. It is not entirely obvious for users to recognize the "next" button at the bottom of the list.
We have increased the number of courses displayed to 50 and there are no negative page loading times as a result of this change. The rational being that tags are usually implemented when there are many courses and it makes sense to have longer lists.
I would recommend to change "5" to "50" so it is "$CFG->coursesperpage : 50;"
Thank you very much for your consideration.