Good review. Couldn't have summed it up better myself O0
I agree that it did feel a bit incomplete in places - Rasalhague's independence and the Ronin War comes and goes in two chapters, for instance. For all that, Heir to the Dragon is still firmly within my top 5 BT novels. As far as "too much, too little space" goes, I suppose there was only so much Charrette (or Stackpole) could pack into a print novel, and more books weren't viable.
My belief is Charrette should have focused on the old vs new ways of the DCMS, delve deeper into the yakuza and how fundamental those changes were for the Draconis Combine. The Legion would have been a good vessel for him to explain the changes brought by Theodore and how it could have clashed with old school soldiers. As much as the pages spent explaining his training in the academy and showing how hard his father was with him were interesting ones, knowing the scope of this novel they should have been spent later in Teddy's life and get better details of what is obviously the focus of this book.
Are there any BattleCorps stories that cover this aspect? They might fill in the gaps here.
One of the best things about HTTD for me was that Charrette humanized the Combine and gave BT some useful grey area rather than the good guy / bad guy characterization that previous novels had delivered. Teddy K and Takashi were well-drawn characters, both flawed and at odds but still striving for the same goal. I came away with the impression that Teddy mirrored the realm he shepherded - flawed but interesting and not simply the evil empire of FedCom propaganda.
Subhash Indrahar was another favourite of mine, a man fond of the father and the son yet willing to work against either or both if he felt it in the Dragon's best interests. The rest of the supporting cast were a memorable bunch, and I often wondered what happened to Esau Olivares (mister feather-in-his-ear) after Marfik. Ditto for Michi Noketsuna, at least until I got my hands on Wolf Pack.
As an aside, I've recently been wondering whether a similar novel, published at the same time and focused on Thomas Marik and his rise to power during the same post-4SW period, might have had the same positive effect for the FWL that HTTD did for the Combine. Bringing the League to life as a faction, ComStar and Waterly's manipulation, maybe contrasting Thomas with Teddy K and their different realms but similar challenges,