Of course if a manufacturer felt - please-  like producing figures drawn for instance from Dr Andrey Evgenevich Negin Roman cavalry (vol 2 incl Heraklian Byzantines) then we'd spend the money

yes, the army of Maurice and Priscus, his C-inC, does seem to have adopted from the Avars to an extent, stirrups certainly but other possibilities; added to the list of reading of source material when I can get around to it - summer earliest

I have a line of reading suggesting some heavier cavalry due to Turkish armour influences changing Byzantine practices - I am sceptical myself and more melee expert might well cover it , if it is indeed a thing at all.

when I have time I'll follow through - agree it is odd

Agree with Nik's other comments

James Howard-Johnston's "last great war of antiquity" is a detailed account from multiple linguistic sources of the Byzantine/Sassanid war that dominated matters in much of Eurasia in the earlier part of the C7 century. It is a life's work reflecting his academic gathering of knowledge since the late 70s, it is also a very enjoyable read.

For the Maurikian byzantine list it suggests the option to upgrade for the highly trained veteran army with which Heraclius launched a series of campaigns into Iran which ended the war. Howard Johnson describes an army which from various sources regularly defeated the Sassanid in open battle and through highly effective pre-battle disposition and harassing tactics. This army was much more effective than the field armies regularly defeated by the Sassanid's in the previous generation. As a holding comment, to be expanded looking to other sources referred to, this might mean that most regular cavalry are superior, some exceptional. Potentially, with crossover with the Turks some elite cavalry might be armoured rather than protected. Armenian, Georgian and Iberian allies appear. There is certainly a very high level of command and control and drill, all referred to in original sources.

The army of 20 years before equally might have downgrading options, performance against the Sassanid became poor and the army demoralised. This is just, as I say, a holding comment until I have time to write some more.

Working out this list is bedevilled by the sources, but at least we have some. To simplify, as you'll know, the previous tradition of military manuals is replaced largely by heroic biographic or by theologically inspired history, the negative nature of the crusader sources(sometimes justified by Norman military prowess), largely anti-Byzantine adds to the complexity, so vast unpicking. I have not tried to access Armenian or Arab sources yet.

Conclusions are clouded and imprecise. Religious art is becoming more useful and the view that much of it was anachronistic is much less strongly held and it may give a fair representation of Byzantine soldiery. Most of my research life is in the world of SMEs. I had promised myself to turn 20 years of interest in the Komnenians into a piece or two  for Slingshot, perhaps 2021 will be the year?