That is a fair point. But.... why dont we have manpower reserves? Ig thats coz levies are irregulars and having "levy reserves" would be kinda weird. But.... then just make it so you can only raise half of your levies at any given time, now you have some reserves, and the justification for that? Idk, someone has to keep your farms and fields operational after all...
Or even just straight up add levy pool.
I dont like that idea, just make battles have like 15% dead instead of current 30 by default. And maybe lower pursuit-to-damage conversion. Coz even right now, minor amounts of pursuit, like one on skirmishers or forest wardens or varangian vets doesnt really do anything coz the enemy almost certainly has some screen from some unit, and that's usually enough to block any gains from your pursuit it completely. Giving levies screen will only make that problem extend to default light cav too probably,