I feel like the character learns and essentially masters their skills too quickly. Granted, I do not play with skill rust on because I quite frankly find it ridiculously stupid in the time-frame in which our characters go through the game, because skills in real life rust through a time-span of a few years, and even if you did forget a few things you’ll re-learn them pretty quickly.
Would it make more sense for the characters to learn skills from levels 1 to 100, but have the experience required to level up be relative to increments of 10? Basically, each level of skill levels 0-10 would level at the rate that characters currently level from 0 to 1, and each level 10-20 would level at the rate of current 1 to 2, etc.
It would allow a more realistic time frame for players to gain skills and would allow a greater level of granularity with regards to recipe skill requirements in my opinion. Of course, it would also require going back and changing every recipe to fit, but would mostly just be adding a 0 to every skill requirement.