Favorites are:
German: MG Platoons, Combat Engineer and Panther units.
Russians:
T34/85, SMG Units (The 6 FP ones) and BT-7 Light Tank
American: 
M-18 Hellcats, Late War Marines
Britian: 
Piat Platoons, Grants
Least favorite:
Anything involving the British 2 pounder, Japanese Armor, 
PA Infantry platoons 
Ivan The Big Wrote:Unis like to see added:
Some kind of hero that would be generated during battle.
I would not want to see this unit.  The game scale is wrong.  Works for Squad Leader, but not here. 
Quote:More on-map aircraft, 
Again, I would not to see this. I don't them as it is. 
What I would like to see is transport aircraft that can land on the board unload / load a cargo and then leave. 
Quote:usable trains that you can load on, 
I am support of this.  I think this would be a nice add. 
Quote:being able to split a unit 
Yes, Yes, Yes the ability to split a unit would be fantastic! 
Quote:and finally an immobile disabled tank that can still shoot after the tank platoon takes a disabled hit.
But disables also occur with knocked out sights, damaged main gun, crew casulties and bailout.  I think the disabled system is pretty good as is.
Good stuff Ivan! 
Thanx!
Hawk