Again, not sure if it fits the sub-board but..

The Character sheets are ok, but with the advancement method, perhaps having an extra page showing off a list of Aptitudes you can 'X' if you get them either with the Regiment or your specialty, with tables 3-14 to 3-18, that'll help players not go back and forth in the book or fill the sheet with writings in every spot. I know this might take a sheet side, so why not have a vehicle page on the toher side? Vehicles are not as Critical as in Rogue Trader, but they still are a central part of Only War. Not to mention the ease it is to get a party as a tank crew.

There's also 6 spaces under the Characteristics Squares, but I suppose the extra 2 are for use later.

This, I think the book could use.

I'm thinking there will be some OW Ascension going on one of these days, that's what I thought since I first laid eyes on the pregen characters. Which kinda means DH power level and RT/DW/BC power level, somewhere in that range.