One thing that does make a swarm army work well is the current backup rule which allows a chump to fill in a break in the line without enduring a charge bonus from it's opponent.
Which I think is fine, albeit somewhat ahistorical, as usually the chump units were placed in front of the good/veteran units to give them nowhere to run (improve their reliability
) Maybe that should be a rule:
If a unit is backing up another unit they both use the courage of the backing up unit.
Hey, I'm going to suggest this for play-test.