I would like to share about some idea about army system. Current system (since the first civ) allow to recruit too much units. When included the resource availabilty as limit was a great step, but we can recruit yet many units of other units without resource limit. The limit of units by resources is ok, I think will be good also to limit a maximun armies (or fleets or squadrons), for example, according size of country (money, populaton, production or all together) availability will be between 2 -10 armies, when you build an army, you can add different units and balance the army. Units can´t be stand alone, they have to be included in army. Probably the limit of units in army will be around 40-50, but if you want to explore you can build and small army (or fleet). With less units, game will be faster.