Louis XXIV
Le Roi Soleil
The thing is that, in the past, defensive UUs have been very useful. The problem with the Minuteman for me is that it's a fairly late defensive UU. If we were talking about a Spearman with combat bonuses in territory, it could be useful for letting you focus on building and expanding without having to build too many units. Once you've reached this period, you usually have a good sense of how many units you'll need to build to protect against neighbors and whether you need to supplement your current troops. It seems the best it could offer is to allow you to disband other units and scale back on military costs (or maybe launch them all in a final war while your new units protect your home).