yeah uhm...

Its nice that you like it... and happy to see a lot of ppl like it... but its just a bad system.
Because in a survival game you should focus on SURVIVAL not on gathering xp as quickly as possible. That is done in RPGs but there, wandering XP dont just come to you! You have to do quest, be at risk or at least time a good while to do the quest, explore the world and stuff.
Here you just leave on 50 torches and a few forges and campfires, jump a bit, maybe shoot your pistol in the air to overkill and boom 10 more walking xpbundles come along.
Zombies should give 50xdifficulty xp. So a nurse is x1 a normal big guy is x2 a fat guy x5 and a military glowing feral is x50 or more.
But even if they balance it, you are still gated behind stupid unnecessary gates that are purely there to spite you.
At that point its not a "do whatever you can to survive" game. Its a "do what we think you like best, because you have no idea how to have fun!" game. Seriously. Difficulty 6 and I only killed about 100 zombies on day 8. 30 were on hordenight. But if I had killed every zombie i saw I probably could already build my own tools, I could carry 6 more items and I could have way more stamina.
But because I DIDN'T farm zombies all day long and actually played the way I liked it, I still have to run around with a stupid stoneaxe, because my two traders only had a knife.
Its not fun anymore. Its a chore. If they balance xp so that pretty much every playstyle gets the smae amount and get rid of the level gates (*)
If they absolutely need some sort of incentive for the player to not have something immediatly, because they couldn't be asked to balance their perks right, at least level it with attributes. So Packmule 3 needs 5 str, packmule4 needs 7 and 3 agility and packmule 5 needs 9 str, 6 agility and 3 perception.
Now I can still get packmule 5 on level 24 (without the first 5 points from the trader) but I still dont have ANYTHING else but the packmule and the attributes. And if I now want a chemstation I need intelligence and perception...
I have given a lot of different examples like raising skillpoints per level and making some perks worth more then others... but that "didnt feel good to level up because you couldn't spend the points where you wanted"... completely ignoring that the levelgates do the same stick but for longer and without counterplay. So I simply think they just have their vision for their game and go with that, only balancing it slightly.
(*)If they REALLY want level gates in there, put all the super benefits(like jumping one/two blocks higher) on lvl 3&5 on 4&5 and lock 4&5 behind 30 and 50. But this is still levelgating.