After reading through this thread, I see both some pros and some cons to this change in the crit rules.
Pros:
- Getting rid of confirmation rolls and extra damage dice speeds up combat
- Keeps max crit damage under control, and favors PCs over monsters by reducing randomness
- Natural 20 almost always provides some benefit to the attacker
- Simple math
Cons:
- Attackers that require natural 20s to hit are just as likely to crit as attackers that hit on a 2 or better
- Natural 20 doesn't always provide a benefit to the attacker, regardless of skill (since they can roll "pseudo-crits" on any successful attack)
- Crits are less exciting because the attacker doesn't get to roll any damage dice
However, this inspired me to think of a potential solution that could maintain all the pros while eliminating the cons...
On a natural 20, the attacker automatically hits, and gets a damage bonus equal to the amount by which they exceeded the required score to hit, or equal to half the maximum of their damage dice, whichever is lower.