So, I guess, let's break each into the difficulty for basic proficiency (BP), the added skill to hit optimal use (OU) and technical complexity (TC). With the proviso that while I've tooled around with everything at least once, I'm not a master of a lot of these, I'd lay it out roughly as:
Greatsword: BP High; OU Medium/low; TC Low
Longsword: BP Low; OU High; TC Low
Sword n Shield: BP Low; OU medium; TC medium/low
Dual Blades (*): BP low; OU Medium; tc medium
Hammer: BP High; OU Medium/high; TC Low.
HH (*): BP medium; OU high; TC high
Lance: BP low; OU medium; TC low
Gunlance(*): BP medium; ou medium; TC high
Switch Axe (*): BP medium/high; OU medium/low; TC high
Charge Blade (*): BP medium/low; OU low; TC Very High
Insect Glaive: BP Low; OU High; TC medium
Comments
Lance = good
Gun = good
Lance + Gun = Gunlance
Therefore, Gunlance = goodgood
Longsword: BP Low; OU High; TC Low
Sword n Shield: BP Low; OU medium; TC medium/low
Dual Blades (*): BP low; OU Medium; tc medium
Hammer: BP High; OU Medium/high; TC Low.
HH (*): BP medium; OU high; TC high
Lance: BP low; OU medium; TC low
Switch Axe (*): BP medium/high; OU medium/low; TC high
Charge Blade (*): BP medium/low; OU low; TC Very High
Insect Glaive: BP Low; OU High; TC medium
Light Bowgun(*): BP low; OU medium; TC medium
Heavy Bowgun: BP medium; OU low; TC medium
Weapons marked with asterisks are ones I've spent the least time with, so I'm less confident with the indications.