A good rule of thumb is that skills should only ever increase through active participation of the player. I don't think Hunting and Cooking should increase from offline activity. You should increase these skills by going to a cooking school, finding a master chef, getting tips from a master hunter, and so on. And if you say that non-fighting skills may increase from offline activity then I'll point you to your own rant about Roleplaying = Fighting!
However, the value of these skills should definitely affect what's happening offline. If your cooking skill is exceptional then you never go to taverns because their food is shit compared to yours. If it's middling then you go to taverns for variety. If it's poor, you make a lot of food ingredients inedible and go to taverns as often as possible, whichever you can afford.
Unlike you, I'm not opposed to players gaining monetarily from offline hunting. At least a little. (As I said, I am opposed to them gaining skills.) The amount they gain should definitely be dependent on their hunting skill of course. There's going to be a big difference between trapping a couple rabbits and getting a tasty doe and field dressing her properly.
Same for blacksmithing. Of course, if you're a blacksmith then you should own a forge! And your Negotiation skill will determine how much coal and iron ore cost versus your products so how much profit you make. You may even gain products that you can sell to other players. And ideally, again the Negotiation skill should only be raised by training in-world. Maybe getting some tutoring from Tom the Savvy Haggler down in the market. Of course, you're gonna have to find Tom first....
Groan, and if you're a Merchant then you should own a shop!! Which just proves how smart and insightful your idea is. But I think having a personal-belongings tax is ridiculously and monumentally stupid. Everything I've read from you is smart and much of it insightful. But this is just stupid. Head tax? Yes. Property (shop, forge, house) tax? Yes. Wealth tax? Yes. Belongings tax? Fuck no. Get real.
And speaking of property, if there's online activity then having a house, which may or may not get burned down in an attack by Orcs ... this again proves how smart and insightful this idea of offline gaming is. Because a house is actually USEFUL. I mean, it protects you and makes sure you're at 100% HP when you log in.
Having a manor house gives you Charisma which increases your Negotiation skill. Having a shack lowers your Negotiation skill and is more likely to be destroyed or for you to have caught a disease offline (further reducing your HP). Imagine logging in and finding out your (untaxed) shack has been burned by brigands, who stole all your gold, and you've fallen ill so you're at 50% HP? :D Well, you get what you pay for!
Yes you COULD deal with banks, for a very, very hefty fee. Or you could risk your stuff getting stolen at your house. Hell, might even make it possible to rob houses by Thieves so all of your non-equipped inventory is at risk. And your housing might determine how much inventory you can keep before having to sell / throw the excess away.
The best part is that between diseases, fires, and wars demolishing cities and hurting the player characters living in them ("In the last week, you were caught in the Great Epidemic of 768"), you've provided them with a really great incentive to get that castle they weren't sure they wanted. I mean, what the fuck's a castle for? Oh yeah, to protect your character!
Having a castle might open up whole new areas of game play associated with waging border wars, subduing your neighbours, and rising in the ranks of the aristocracy. Also a castle allows you to call for merchants to come to you instead of going to the market, for a premium. But then again, every time you go out, you'll have to decide whether to disguise yourself (losing your Charisma and Negotiation bonuses) or going out with an armed guard to deter brigands.
The best part is that if you're offline for a year then your castle's been taken over by your neighbours (who've waged a 2-week war against you in your absence), you fled to a manor house with your possessions which all got robbed by a thief, you could then only afford a modest house in the city which got burned down to the ground, and you're now living in a shack with tuberculosis. Which is why you only have 50% of your HP and lost all of your non-equipped inventory.
(In Asheron's Call, they had thieves robbing houses and people quit in droves. But the reason they left was because there was no way for players to protect themselves from the thievery. It turned them into helpless victims and such things can never be considered game features. If thievery was merely an obstacle to be overcome like every other game feature, it wouldn't have produced so much protest because it wouldn't have sucked so badly. The same is the case for player killing which players can't do anything about because they aren't allowed enough control over the game mechanics to institute effective punishments. And because there's no penalty or repercussions (like say losing resurrections) from criminal activity.)See? No need to curve down anything artificially. Just add some random punishments that attentive players have to deal with every few weeks or months and an inattentive player will get burned by them after a year. This is why I have absolutely no problem with players getting monetary rewards for their skills. And for those players who don't have a castle to lose, nor any non-equipped inventory to get robbed, nor a wooden house to be burned down? I have one word for them: pregnancy.