Dear DotS Team,
first of all I have to say that I am amazed by your preview and I am really looking forward to play your super-mod. You have put an amazing ammount of work into it and you have my deepest admiration for that!
I just have a minor suggestion for your consideration regarding the evolution of Bohemian Kingdom. I think it might be worthwhile to consider one more change of that faction name beyond the Kingdom stage. My point is that from a game-play perspective it would be rather odd to see this kingdom to expand over the Europe AS "Bohemia" (or Czechy). This name historically belongs specifically to the area more or less identical with today´s Czech Republic (minus Moravia) which is on top of that rather firmly geographically and ethnically defined.
However there is a historical precedent for a significant territorial expansion of the Czech Kingdom under the rule of Kings of Luxembourg dynnasty, namely under the Czech King and Roman Emperor Charles IV. in the second half of XIV. century who acquired Silesia, Lausitz (Luzice), Pfalz, Brandenburg and other counties and duchys adjoining the "Bohemian" core of his domain. His concept went far beyond "personal union" by the person of the ruler (like the Polish-Lithuanian Union, and others). He did so by INCORPORATING the new land to the Czech Crown thereby inventing a new term "Corona Bohemiae" which stipulated that the land did not "de iure" belong personally to the King, but rather to the divine ruler of the realm St. Wenceslaus and therefore that the King is not - as was usual at those times - free to transfer (sell, lend, etc.) these lands, or parts of those, to others but that it is his duty to preserve their unity and prosperity. This legalistic conception proved rather successful and survived long after the land of the Corona Bohemiae were acquired by the Habsburg dynasts and formed the core of their new empire 200 years later.
I would therefore propose - as expansion of Czech Kingdom beyond its historical borders is likely likely to happen in M2TW-based game to introduce another stage of development beyond Czech Kingdom (or use the term "Corona Bohemiae" or "Koruna Ceska" instead of Czech Kingdom.
I, for one, as a player would feel much more comfortable to expand my faction by "incorporating" new territories to the Czech Crown a la Charles IV. rather than to set out on a conquering spree enlarging Bohemia-proper which would seem to me too ahitorical and inappropriate.
Of course it is completely up to you to decide whether the merits of this suggestion would outweigh the work you have already put into it and the mor work its implementation will have incurred. But if it as simple as changing the faction name, I think it will be worth trying.
BTW, the coat-of-arms presented in your preview for the Kingdom stage already seems more appropriate for "Corona Bohemiae" rather than for the Czech Kingdom proper, which would be simpler and feature just the silver lion on the red field.