Another problem with the d20 system is the attack-bonus vs AC spiralling out of control. DCC does this as well, but also points to other solutions:
– using a die rather than a fixed bonus, meaning there’s still a chance of failure
– larger crit range (i.e. you crit on a 19+, then on a 18+)
However, the above things only apply to the warrior and dwarf.
So here’s the idea: Every other level, you get no attack bonus. Instead, you get a damage bonus. This way rolling to hit will still be thrilling, ACs easier to balance and you can maintain the low-level grit feel for a longer time. Every third or fourth level instead of attack bonus or damage bonus your crit die increases, meaning you will deal more damage when scoring a crit.