One of the things that always seems to skew the game is automatic weapons. Maybe that is why I like my "colonial" actions from about the 1650s through the late 1700s. A half dozen Soldados trying to retrieve run-aways, stolen livestock, goods from the native forces (or a nice raid/ambush by either side.) Escopetas are not maxims. Alternatively, escorting refugees heading towards the possibly questionable safety of a presidio or mission can be a challenge for the colonizing forces.
Creative terrain allowing unknown forces (or terrain that isn't quite as it appears initially on the table - "That wadi was NOT in the report, sergeant!!" "If we live through this, those scouts will be cleaning the stables for a month, Sir!") - to surprise the non-locals is an element I think in many colonial games.
Gracias,
Glenn