Extrapolating damage at +1 per 2 ST over min ST, I get 2d+3 for a ST 18 War Axe, not 4d.
http://www.draconiansimulations.com/...justments.html
It does seem to me that there should not just be a generic one-handed or two-handed club, but larger and larger clubs to achieve the full damage.
And, there should be larger versions of actual hand weapons, for giants, etc.