Another good option for Crits is to say when you roll a critical hit, any number on the dice below the "average" is treated as the average.
Normally, a Raging Barbarian's Greataxe critical would deal 2d12+5, or an average of 18. By assuming any number below 7 is equal to 7 (as I said "average", similar to if you take the "average" hit points) meaning any dice result of 1 through 7 is treated as a 7, putting the average up to 21.5.
This method, while raising the damage slightly, ensures the dice rolls do still matter, as well as ensuring it is not possible for the critical hit to roll poorly (in essence it actually prevents the critical hit from being below a normal hit, since double the average of any dice using this method would be greater than a single dice of the same type could achieve).
Normally, a Raging Barbarian's Greataxe critical would deal 2d12+5, or an average of 18. By assuming any number below 7 is equal to 7 (as I said "average", similar to if you take the "average" hit points) meaning any dice result of 1 through 7 is treated as a 7, putting the average up to 21.5.
This method, while raising the damage slightly, ensures the dice rolls do still matter, as well as ensuring it is not possible for the critical hit to roll poorly (in essence it actually prevents the critical hit from being below a normal hit, since double the average of any dice using this method would be greater than a single dice of the same type could achieve).
