One of the things I like less from Rolemaster is that all you know from one thing can't be applied to another, and, at the same time, you can not specialize in something.
You either know One-handed Weapons or not. But you can not use that knowledge to help you with a Two-handed Weapon, even if they are the same big sword you just want to use two-haded to make more damage. And you can not specialize in curved swords so that you practise and learn on them, since all your practice (XP) with a short curved sword applies exactly the same to a big straight sword.
I think there should be a tree-like system in which e.g. you learn "wield" for three degrees, then "wield swords" or "wield hammers" for another three degrees, then "wield straight sword" and "wield curved sword" for three degrees more, and so on.
It is not about arms modifiers, it's about specialization. Two equally trained players, trained with the same sword, in a duel in which they are given different swords, should have different characteristics based on how much similar that sword is to the one they were accustomed to.
Is there some such a system for Rolemaster?