Incomplete series?
The characters get flatter and the battles move to center stage. That highlights the impossibly small unit sizes, both ship crews and ground forces. The battles become less and less plausible as a military backdrop to the story. The structure of the Commonwealth government and economic foundation is still skimpy. It's non-existent, really. That was the part of the books that would have interested me the most. The fleet itself is either a lost cause (endemic stupidity and/or acceptance of bad practice) or its efforts to become effective are obviously (to officers and sailors alike) being stymied at the high command and civilian government level. Exploring those possibilities would have been a nice story.
The battles are washed out scenes, since the emotional connection to the characters is so tenuous. The ship types and sizes are weird (Mixon did a much better job of that in another series). The small unit sizes are well below what the story calls for. At one point, a corvette has a crew of about 4 sailors but 8 boarding troops? Trust me, that doesn't work in so many ways for any value of the classification of corvette (a lot of naval classifications are or have been specific to a particular navy and aren't really universal, try identifying landing craft in Wikipedia for example).The writer mentions big unit sizes like divisions and brigades but is limited in his experiences to writing units no bigger than a large squad or short platoon. Likewise his ship crews are small not because of tech but because of limited naval knowledge, I think.
Commandos which is a very vague term (see Boer War references for the origins of the term and British Army usage since), seem to include every ex-marine pirate in the story. Mercenaries with no ground force or marine background can outfight them every time? This is an example of what combat might look like to a supply clerk in an airborne unit or a videogame warrior perhaps but knife or gun skills are not the total or even most of what a soldier is or does. There are so many other holes in the action that making the book about the battles, makes it impossible to overlook them in favor of character insights or relationships.
I wish that the book had more punch but it still is an OK adventure story, albeit with thin characters and background. Don't look too closely and it can be fun. The series seems to just end with no resolution of the background questions. Maybe there will be more but the story is unfinished. I probably wouldn't bother to read it anyway.