Run / Walk speed is not calibrated for AI and human. AI moment slows down game play when waiting for AI to negotiate basic obstacles or open terrain with no immediate threat in the vicinity. It is very easy to run off and leave your AI team behind, and it takes a while for them to catch up.

Another note to AI performance and appeal,
AI stall sorting formation orders out, which detracts from the realistic effect of having competent AI mimicking trained soldiers.