I was at first appalled seeing a French Army organised in Columns as the Allies in Austerlitz. However, I can live with it and I understand it was a decision to simplify the problems of developing a working AI (which Histwar certainly has). This is certainly a major thing to consider for the scenario designer, who has to decide what "Groups" to introduce into the OOB to cater for the better (which might mean more historical or not) enjoyment of the experience conveyed by the scenario.
At the risk of sounding patronising, which I don't want to be
It is up to you as the CinC to decide on the formation your Army Corps are going to fight in, don't like Column, change it mate. That's what HLG is all about, YOU are the CinC not the Scenario creator, he is just giving you an OOB, Deployment and a Map, up to you how you use it. If a Scenario creator has put the Army on the Map in "March Column", he is not infering that this was somehow a "Correct" deployment, he merely presumes that the player will make his own deployments in the "Initial Deployment Phase"