How about adding a new Building for All Races
Named Training Pit
Will work similar to Training in Citys
but will not be Limited to Racial Units means you can Train Any Unit in it.
and will not Cost Gold but Time instead
You Send two Units to the Training Pit
and they Fight each other slowly to gain Skill Points
You can Set em to Fight to 50% 10% or to Death
Fighting to Death will count fully like the Unit would Fight an Enemy Unit (but will cost one of the Two Units)
Fighting to 50% will only make you Gain Experience at 20% rate
Fighting to 10% will make you Gain Experience at 40% of the normal rate
Once the Units Finished their Fight they will leave Pit and be under Controll of the Player again
having gained some Experience and of course being Injured and need to be Healed first before entering Pit again
Also to have this make some Sense Units Trained at Home should be able to Reach not only lvl 5 but lvl 8 :P
In the Shadow of the Black Cross. We Fullfill our Duty in your Name.
And Look forward to the Day we Return to your side Silvanos.
Watching over our Comrades as they Fullfill their Duty in your Name.