Adventurer Conqueror King System RPG are damn near impossible to pull off successfully as written.
Acrobatics requires a roll of 20+ to successfully tumble in combat, which would infer the +2 mentioned earlier in the proficiency description applies to this roll to, making it effectively a roll of 18+ on a D20. Why even bother?
Knowledge checks succeed on a roll of 11+, bu the PC is consider an expert in his or her field? An expert is only successful 50% of the time?
How about the healing skill? If the PC takes the skill twice, on a roll of 18+ he can neutralize poison, cure disease or cure light woulds. 15% chance, and it takes two skill points to even have a chance.
Did I mention that you don't get to add an ability modifier to the proficiency rules as written? That was probably the first thing I houseruled into the ACKS system, and it hasn't broken anything yet.
I simply ask the player the first time a proficiency is used that requires a proficiency check "what ability do you think would apply to that skill?" They explain their answer and if I agree, we make a note of it and the ability score bonus carries on for that skill whenever it may crop up. If I don't agree, we discuss it until we find an answer that does, even if that answer is "no bonus".
From my perspective, making the proficiencies more usable makes them more relevant and makes the game by extension that much more fun.
The Atlas of Pern -
2 hours ago