I dont like the proficiency rule for skills. It's great for attack/saves for bounded accuracy but I would like to see skills be more customable.
It would be great if you get some amount of skill training per level and every skill could be trained 5 times. 6 times for expertise.
1st level training would give +4 to that skill
2nd lvl training would give +7 to that skill
3rd lvl +9,
4th lvl +11,
5th lvl +13,
(6th lvl +15),
Expertise would be free level of skill training in already trained skill.
you can have 2nd training at lvl4, 3rd at lvl8, 4th at lvl12 and 5th and lvl16,
expertise is added extra over lvl limit, so 1st level rogue can have +7 to two skills and possibly +15 at lvl16 if he trained that skill 5 more times.
all classes and races would get their normal amount of skill training plus extra per level(including first).
Fighters, wizards, sorcerers,clerics,paladins would get +1 training per level. (20 skill trainings extra at lvl20 plus starting class and race).
barbarians, druids, monks, warlocks would ger +1,25 training per level. (25 skill trainings extra at lvl20 plus starting class and race).
rangers would get +1,5 trainings per level. (30 skill trainings extra at lvl20 plus starting class and race).
bards would get +1,75 trainings per level. (35 skill trainings extra at lvl20 plus starting class and race).
rogues would get +2 trainings per level. (40 skill trainings extra at lvl20 plus starting class and race).