Ex:
North Euro factions (tutons, rus, lith, pol, den, ect...) = bonus fighting in snow, large penalties in desersts (less morale, less movement, get tired quickly)
central euro (eng, fre, HRE, scot, ect..) = no bonus in snow, penalties in desertes
South euro = (italy, spain, ect..) small penalties in snow (lower morale, less movement), sightly lower penalties in deserts
Anatolia/asia minor = (biz, turks, ect..) no penalties in snow and lower penalties in deserts
Middle East/Africa = (moors, eygpt, ect..) large penalties in snow (very low morale, low movement), large bonus in desersts (plus morale, plus movement)
units like camels and elephates sould lose numbers when they are in snow for to long because they cant survive in such cold conditions
also would it be possiable to have large stroms like at sea but in winter regions to represent blizzards that could devistate an army when it is out in the open
i think this would add a new layer of complexity to the mod and force the player to realy plan out his campains