RCM-Native has always been a developers' tool. It was never balanced for long term playability, nor has any claim been made of such.
However, as a developers' tool, it can be extremely useful to see what kinds of equipment interact in what ways. Long, relatively light swords SHOULD be ineffective against really heavy armor ... if they are not, then we have a problem with the stats.
Any substantial mod will have to design the equipment level to reflect this. This is true no matter what model you use.
Don't forget, however, that balance can be developed in other ways. Mesoamerica has excellent game balance, in spite of one side having top-end Spanish steel from the very high point of Gothic weapons and armor, and the other side being neolithic. That's because the neolithic side has a LOT of troops, and they're tough, fast, and as well-armed as neolithic people can be, while the Spanish suffer from low manpower and apparent supply shortages (i.e. not all of their troops are as well armed as one might think) that render them quite vulnerable. ONR, also, draws a deliberate contrast between samurai and peasant equipment - like a T-72 rolling onto the field against a bunch of modern farmers with squirrel-rifles. Balance there is developed by the high cost of equipping and maintaining samurai.
So if you're working up Band of Warriors, or whatever, consider non-conventional ways of developing balance. It can be very rewarding.
Assuming, of course, that I can ever in my lifetime get the bloody formulas figured out. They seem to make no sense at all, considering what I knew about the previous ones. This is an absolute programming nightmare.
Everybody ... please, help. I need to know how the base damage formula works. If you don't know, collect a bunch of numbers and guess.
Damage used to be random between 50% and 100% of rated value, then minus armor (calculated the same 50-100%). Now, either that has changed, or huge bonus factors have been added for various reasons ... I can't tell which.
Until this is decoded, THE RCM .89x IS NOT READY FOR USE.