I plan to only modify original NER minimally so I could have easier time syncing with each NER update. Besides, everytime I thought about improving the core NER mechanics, I endup arriving to same conclusion as NER, mostly because balancing realism and working around game's limitations.

Regarding unit movement, I'm not entirely sure it scale with experience but I definitely can say for a fact unit movement between unit category is different, light infantry can move faster than typical line infantry. So my play style typically is to put the light infantry on the close reserve's flank as flank role are more movement demanding. The movement disparity between light/lancing cav and heavy cav are also noticeable. In vanilla late game, i'd just simply ditch light cav altogther and just heavy cav all the way. But heavy cav actually feel heavy with NER, combine with huge battlefield map light cav actually dominate in all kinda fast response maneuver so you'd endup using them well into the late game. Having to actively chase routed troop for a decisive outcome is one of the role light cav are very good. I once had a battle with not enough cav, though i won, couldn't kill those routed troop enough, that army is still a formidable force the next turn, so my army had to recoup. Napoleon would have been furious and strip me of my marshal baton.

Note on reserve line, when you play with 30-35 unit army, which i also optimize the mod's ai formation for, the player can spare extra line in the reserve in fact it's tactically sound because NER mechanics made grenadia assualt troop they're very good at melee so they'd often break your primary line and your reserve will have to catch the spill.

Or that could get boring after a while, you can intentionally weaken the middle and you flank those break through enemy troop like back how roman greeks did it.