1) I only reported my interpretation of the rules up above. If you are not happy with that, then change them for YOUR game. I had nothing to do with the design of RMSS/FRP.
2) In the original RM rules (and core RMC rules), to use a 2 handed combo, you had to know both weapons, but there wasn't a special skill just for it. It was basically automatic so long as you had the other skills.
3) It was Rolemaster Companion II that introduced TWC as a separate skill, and it required learning a weapon skill for each hand as a separate skill. This is what was carried over into RMSS/FRP.
4) The Combat Companion, which can be used with RMSS/FRP has TWC being a single skill, without any prerequisite skills. The skill will have a higher cost, yes, but it is at least a single skill.
5) Most european combat used single weapon and a shield, or 2 handed weapons. It wasn't until dueling came into fashion that two weapon combos began to appear. In France you had weapon and main gauche. In Italy, you had a light weapon and a cloak most often (IIRC). And this can likely be traced back to ancient Rome and it gladiatorial days when the gladiators fought with a short sword or trident and a net (mostly guessing here hehe).
6) If you look at those cultures who did use two weapon combos, you'll notice something. Every single one of them used light weapons. Long Swords and/or Broadswords were rare, mostly you had rapiers or sabres, 2 short swords (i.e. butterfly swords), two short sticks (escrima sticks), etc. Never any really heavy weapons.
I think that about covers everything..