The Minutemen are generally looked upon as 'farmers with pipe pistols', but the people who say this generally don't realize that it is the player's job to arm these soldiers. For example, I have armed The Castle with 23 soldiers with full heavy combat armor and Gauss rifles. The 'Defend the Castle' quest is a cakewalk for them. The Minutemen are designed to be nothing without the player, as they are the player's own faction. In fact, the Minutemen could easily destroy the Brotherhood of Steel, and the player can have them do so in 'With Our Powers Combined'.

Next playthrough, go ahead and outfit these farmers to be verifiable killing machines. It's fun.