Hi there,
first i wanna thank the Devs for the Game. It´s challenging but not to hard and it´s fun to play.
Some Ideas for what might be a good thing for the game to implement.
I would like to see some new skills and items which need 2 skills to build for specific professions.

Trapping :
Put in a trapping skill and give us the chance next to hunt/farm/gather to obtain food.
The Skill could be raised only by using trap of diffrent quality and for diffent animals.
To start there could be a crate/box trap for small animals like rats/hare (new animals could be rats/mice/snake ) and a sling trap for birds. Later on get more advanced traps with more advanced materials. Like skill 30-50 with a Iron bar box to trap boar/bear etc. should be a need to kill the animal in the cage, but there is a chance that it brakes free. That way single player would have a chance of the rare bear skin, but still the danger of getting killed by a enraged bear out of a cage. The Trapbuilding should be connected to 2 skills like 10 trapping and 15 woodwork to create a diffrent/better kind of wooden trap or the like with smithing for a ironbar trap. The higher the skill, the better th trap, less chance of breaking free. The better Trapping skill, the more likly you catch something ( don´t think a bear or boar would walk into a plain steelbox, but more likly in a good camonflaged one).

As others allready have suggested, but i wanna give a bit detail to it.
The skill raises by go fishing and you can obtain more/better fish with higher skill.
To start you could use a simple stick like the wooden spear. At skill 5-10 you could build your first rod (stick + thread+copper nail (just think it´s bend to be a hook)) the higher you skill get´s the better rods you can build with higher woodwork. The better the rod/skill the bigger the fish and higher chance to catch it. Maybe at skill 35 in wood work and fishing you masterd to get the blueprint for a boat (maybe with the skill system have a logboat first and later more advanced once, which just last a certain time on water (time on water reduce durability, like running reduces stamina or other works reduce the items durability)).

just some addups to the current system, could be skill 10 seed/harvest 2x1 skill 20 seed/harvest 3x1,skill 30 seed/harvest 2x2 , skill 40 seed/harvest 3x2 skill 50 seed/harvest 3x3. Add some fruits like potatoes, peach and pear for more farming stuff and also cooking/juicing.

get the ability in combination with other skills to make some cloth. You could make a job specific cloak, for example camougflage cloak for hunter (better chance of crit on animals or a slightly increased amount of stuff you get from skinning) or farmers cloth to use less stamina and/or have a slight higher harvest and/or growth time. Also with higher skill produce better thread and ropes for other professions , example would bet better fishinglines or diffrent ropes (ropes for Siegemachines need to be stronger than ropes for catching a horse), so the Tailorprofession gets somekind of better use and daily wear ist diffrent then leather or mail cloth, at least i haven´t seen anyone doing daily chores wearing a platearmor to plow fields or cut down trees.

In generall this is for now just food gaing stuff, but i come up with more later on.
The basic about this thougts is getting a bit new stuff, some rewards for using your skills and combine skills to get some stuff a one sided player can´t make. A fisher won´t most likly not be able to find the best wood for a rod or fishingline as a tailor and a hunter is less likly a good farmer or smith. Makes more up for trading and specilizing in skills for both types of server/gameplay.

I know it becomes at some point overwelming with stuff to create for one player, but thats the idea behind. You still can achieve all as a single player, but it would be easier to work as a group/guild to specialize each char.