I'm sticking with my initial suggestion. If you want to make certain tags mandatory then those could be the ones you might categorize by so that you have a way

I'm sticking with my initial suggestion. If you want to make certain tags mandatory then those could be the ones you might categorize by so that you have a way of letting people explore your content through browsing. Still, the decision is easier than choosing your categorization criteria and then populating all of the values.