I personally think some people end up using some tag Just to fill up the 5 tag requirement(i did that). Reducing the number of tags might not be too great an idea.
But i think a reorientation won't be too bad an idea, you can create an article that would contain the neccessary requirement for a particular tag, what exactly a post Should contain to be eLigible for a particular tag.
And i think creating more tags too can be a great idea.