I drew a slightly different conclusion from the text than you guys. I thought the Draconis Mech brigades were named after the senior most regiment in the formation. I.E., the 4th SoL brigade was such because the 4th SoL regiment was the oldest formation attached to it, with the other regiments following its lead. Maybe the commanding general of the senior regiment had control over the whole formation with the rank of sho-sho. It does seem that the tradition of certain DCMS regiments having a general officer commanding it would have been rooted in that practice. All speculation of course.
The AFFS listings didn't really surprise me. I knew from the Field Manuals and other sourcebooks that a good chunk of House Davion's modern forces were formed during or after the 1st SW to replace the huge number of traditional forces destroyed in Minoru's offensive and the debacle on the Capellan March. It will be interesting to see that fleshed out in future materials. That DLC listing was confusing though.
All of the other regimental descriptions were nice enough as well, although the FWLM got kind of shafted there. What? No new provincial military units? If the Mariks had 190+ regiments by c.2785 and canon sources only account for about 90 or so, then there is a whole load of unknown units out there that have not even been touched upon. I do expect to see more on that in the future.
Finally, the SLDF got me really excited for the upcoming FM. A lot of those divisions seemed to have specialized ToEs, which makes them stand out a lot more, and the Special Forces command was a lot bigger than I had assumed. It seemed to include entire brigades of specialized Battlemech units among other things. It also seems the SLDF was starting to contract even before the Periphery rebellion. Those "bandit" raids must have been really bad if an entire Battlemech division (the 3rd) could be ground down by them. I guess we will have more details on that in the next few months.