When it comes to Masterminds I've found pools to be more of a personal preference flavour than a 'must have for build success.'
Here are some thoughts:
Thugs are squishy, consider Leadership pool for added protection.
MM henchies often get lost/stuck. Consider Teleportation pool to bring back your stragglers.
Few things in the game resist Fear: Consider Presence pool. Also: using Provoke and Bodyguard mode is a tactic many MMs employ.
Invisible henchies for fun and amusement. Consider Concealment pool.