@JohnK. If i may make a suggestion. I suggest instead of the skill points costing more overtime that you simply block out whole trees, but allow everyone to get the 1st tier in every tree and everything in one or two other trees. I.e. if you want to be a smith you research the whole tree that is involved in it, but you can still farm, hunt, gather etc etc but you wouldnt be able to say cook advanced recipes as a cook. You could even have an admin server option that lets you pick by clicking on a box... 1 full skill, 2 full skills, normal mode. Keep both sides of the fanbase happy.
I suggest this because i have tried it on a personal server with a few other people and it had good results for server size. I allowed people to specialize in 2 tech trees fully (opens up more gameplay for everyone while encouraging trade) i also allowed everyone to fully deck out the survival tech tree (allowed for everyone to do manual labor and not grind all the time) and also allowed them to learn one tech block in each tech tree (i.e. you could either learn the 1st level of carpentry or the 1st level of paper, not both) doing this allowed for the game not to become impossible if others werent on. You could still farm your own land and such, but not nearly as efficently as someone fully decked out in the farm tree. You could still cut boards, but someone specialized as a carpenter would use a lot less wood and be quicker.
If you need any further explaining or help im here to ask
This is a great way to do it, But to add to your idea here.
I would suggest not making the gathering skills such a pain to use. first level costs 1 skill point second costs 6 and it only reduces calorie consumption by 14%. that means for the first ~6 hours of gameplay it's grinding for food. And this is just for getting level 2 of a gathering skill such as logging. That second level drops the calorie consumption from 107 to 92 so it's still a grind for food. No matter what food is always needed even in the later game, which is why I don't understand why it's so high when starting the game.