Thanks a lot for your extensive reply. Much appreciated!!!
pwb3 gave more precise information.
I will just add on.
Robes: Once you get to Monk onwards, none of the unlocked characters can use Heavy Armor, and only the Headhunter can use up to Leather and Scales... thus some people will pay a lot for Scales with the right Modifiers... basically Feeder, Samurai & Paladin can use Scales as well, so they can be used from reset.
Lightning & Wild Heals are the only 2 charms a Headhunter can use, however 99% of the rest of the characters can too... only the Guardian can not hold any Damage cast charms (Lightning etc)
Heavy weapons are rare, but some people do like to use them, the base damage is double compared to the counter part... Lonsword vs Sword, Club vs Warhammer etc. Most sort after is Battleaxe... not sure on others opinions on heavies, but I use them a lot, so my order of preference is;
Longsword: Feeder, Samurai, Paladin can use.
Battleaxe: Feeder, Paladin and Headhunter can use.
Spear: Feeder, Monk and Ninja can use
Polearm: Feeder & Paladin
Warhammer: Feeder & Paladin
I pretty much play all my characters, I do not concentrate on building one character, so I no longer try to reset ladder or unlock a headhunter, thus I pretty much end up with Paladins, haven't found enough gear for Monk setup, so I hardly play them.
To each their own, hope you enjoy the game and keep at it.