I understand the difficulty with combat, people have tried in the past to replicate Warband's combat, but the mesh's skeletons are far more complex and the animations have to entirely be recreated, which isn't as simple as it seems, I think if it were to be that simple other NW clones like holdfast and bcof would've implemented it.
With Bannerlord it's even worse because how the combat works is fundamentally much different than Warbands, with different damage arcs, armour penetration and all that stuff which Warband doesn't have, so even if they manage to replicate the animations from NW, how they'd play out would need to be completely re-imagined from what Bannerlord currently offers which adds another amount of complexity outside of just using the animations and replacing the models and slightly changing some animations (which seems to be what's happened here to some extent).
Bannerlord over-engineered their combat and had far too many values which is why most of the damage values are completely different from each other, shit like stances on top of terrible animations just caused the combat to feel less fleshed out than Warbands even though fundamentally it's much more complex, balancing happens every patch to no avail, thus obviously trying to change something that's so deep in code just seems like a ball-ache that no one really wants to hop onto. I don't even think the modding tools even allow that, only to change values of the systems.
I do think NW's combat (much like warbands) has plenty of flaws which never got ironed out and having NW-style combat with more fleshed out animations would probably be best, though I don't doubt the complexity of that.
