For full stack armies (15+ units):

Generals - max 2
Knights - cavalry or foot, max 8 units inc. generals
Total cavalry - maximum 8 units, inc mounted knights and generals

Artillery - maximum 2 units (5 in a siege)
Foot missiles - maximum 6 units including artillery

Zweihanders, halberdiers & other heavy infantry, max 4 units

Spears, pikes, peasants, town militia etc - unlimited


For half stack armies (7-14 units), we just halve the above.
I like this idea much better. My biggest concerns were that generals were not included in knights, artillery had their own extra slots outside of other missiles, and that "other cavalry" section that could have potentially put an army at 14 units of cavalry if it had 2 generals, all mounted knights and then 4 of those "other" cavalry.

Ok, I'm happy with this. Let the gaming commence!

Oh, one more idea though, regarding who decides the composition of new armies.

When an army needs to be raised for offensive action against an enemy. Who should really determine the whole composition of the army?

For this, I think the best idea would be to first of all decide which duke or field marshall is going to be directing the campaign, and then for the duke or field marshall involved to work out the desired army composition with the chancellor. I don't think this would be too difficult, nor would it slow the game. It's a simple exchange of "Chancellor - Ok, we can afford two half stacks, whats your preferable unit list for both in this invasion?" "Duke/Field Marshall - Ok, it's Italy, lots of better quality militia than our own, little cavalry...Give me a solid core of 6 armoured spearmen, 1 general, 3 militia crossbows, 3 mailed knights, and 1 catapult."

Or, alternatively, the dukes/field marshalls of each individual Ducal House can deliberate quietly with each other to develop a "Standard" army composition for their House. That way each Ducal House has a unique army composition and the chancellor, when creating an army to be lead by that house, can simply refer directly to already established doctrine and put an army together according to their standard.