Thank you for advice.

I am so enjoying my old version of MTW that I do not want to start play VI and XL version for a long time (even though I really look forward to play Cumans, Bulgarians, not mentioning all the Saxon factions etc.).

However, I will install V1.01 patch after your kind advice. The question is: will I be able to finish my current campaigns (on V1.00) after patch installation? Sorry for a stupid one...

Regarding buffer zones and re-emergencies - sometimes it becomes a real challenge if you fight deep in Central Europe, and suddenly a faction reemerges in strength behind your lines...

That is my single objection to reality of MTW play. There would be no chance in medieval Europe to keep huge empires as you often command in mid-game. Feudal lords and neighbors would tear sooner or later your kingdom apart.
The Shogun and unification of Japan is quite realistic concept...

Still, it is the best strategy game I have played on PC.