[Polydamas]

Just one example: Axe/Mace defaults to Flail-5 or DX-5. However skilled you are at Broadsword or Shortsword, pick up an axe and you are relying on raw DX in GURPS.

In the real world, there is very little evidence for any special training program for axes, hammers, and maces in western Eurasia, even amongst the kind of people who were expected to know how to use one. Most warriors seem to have taken the view that if you could use a sword, you could figure out an axe, hammer, or mace. So I would have the different one-handed Melee Weapon skills default to each other at no worse than -4. The duellist focuses on a single skill, while the combat soldier buys several (giving defaults in most weapon skills) and probably buys a few others up from default.