Thanks for the input.
See, the problem with being able to unequip your pack is that could cause a lot of issues on an online game. With online games, there is a good reason you can't change your inventory. I'll look into it but I can't make any promises. However, nested containers inside of your main pack (such as bags or belts) do work as they should.
I'm going to use Free Hand specifically for consumable items like potions, scrolls and spell books. I may eventually implement a duel-wield ability that you can learn at a certain level, allowing you to equip a weapon in the free hand slot for increased attack strength.
I'm not going to add a job system actually. I am going to do some kind of skill tree though. There will be both regular abilities and level abilities. The regular abilities will be by themselves and can be learned with a spell book (like fire bolt, cold ball, heal minor wounds) and the level abilities can only be learned by reaching a certain strength, intelligence, constitution or dexterity level. Some level abilities will be taught to you automatically as you level up your stats, others you'll have to do a quest to get. The regular abilities also have level requirements but you have to buy them, and only the level abilities will have a tree that you can choose from. Idk... I'm just thinking out loud at this point.
Glad to be helpful somehow.
About the skill tree
it looks like complex what you're developing (many ways to obtain certain skills), but sounds interesting. However, I think that if those "skills" come from different sources (levels up, quests, abilities' scores, books) you shouldn't classify all of them as "skills"; you could organize such powers
into different categories, depending on their origin. Just an idea.
Consider D&D 3rd edition game for example: there are skills, but there are also feats; they work, and are obtained or developed, differently. You can also have proficiencies (like weapon, shield and armor proficiencies...; however, the "weapon proficiencies" had an interesting and particular rule distinction from other powers in the AD&D 2nd edition; I think it was related to points used; as for D&D 3rd edition, the proficiencies are simply included in the general feats' list, so they are just common feats after all), special abilities (from race or class), and magics of course (which would be a special ability from a spellcasting class, but this doesn't matter here as there might be no jobs actually).
You could also consider Ragnarok Online game reference, where there are Active Skills and Passive Skills, an interesting concept stressed out in that game. So for example, the category of powers which would be achieved buy books, could be all Passive powers.
(((((((((((Concerning Skills, have you played Ultima Online?
That game is interesting as a MMORPG (not only for buying/building houses and the possibility of getting a mount or ship), but because there are such uncommon skills (at least for most common hack'n'slash MMORPG) as mining, fishing, cooking, lumberjacking, tailoring, blacksmithy and so on (not that the way they came out to be applied in the MMORPG system was any intelligent; but the main idea was cool; might as well have been based somehow on AD&D 2nd edition skills' list). Well, now, I'm not suggesting CotW Online should have such kind of skills! But I believe it would fit somehow the gameplay, if ever it was feasible.))))))))))))
Now, back to the more 'useful' powers:
Ragnarok Online has an interesting set of both skill tree and spell tree.
Imagine the CotW spell Detect Traps. Well, in the first 'level' of this learned spell, maybe it is quite weak and only detects up to 1 or 2 trap per casting, and quite close to the character. But if you spend more 'points' (or develop it whatever does that mean) on it, it can improve a lot more in many different ways. Also, to have the spell, or to develop it to a certain 'level', could trigger-open the spell tree branches to get other useful spells (as in Ragnarok Online spell tree).
In the single player game Might & Magic VI,
there is also an interesting skill concept:
the Basic, Advanced and Expert features.
You can spend as much points as you like (and have available) in one particular skill, let's say the "Repair Item" skill. It will improve with more points. However, until you're not taught to use your skill in a more sofisticated way, [taught] from an Instructor or a Master NPC (which sometimes are hard to find, in inospitable locations, or gives you a challenge/quest in order to accept teaching you, and some even ask high prices still...), you're will never get the best of that skill. Instructors train you into Advanced level, and usually asks that you have spent at least 4 skillpoints on that skill in order to teach you; Masters train you into Expert level, and only if you're already an Expert; it usually needs at least 7 or 12 skillpoints used up on that skill. A skill in the beggining is always at Basic level.
In that game, spells were learned from spellbooks too,
but you could improve your magic powers as if they were skills, with the difference that there was (for example) a skill of "Fire Magic" (which would affect ALL your spells from the Fire domain); so no needed to spent skillpoints per spell, but for magic domain/school.
Well, those were just some game skill concepts of the best references I remember about. Feel free to discard everything, or modify if get any nice vision from those stuff. Good luck for the skill tree anyways.