It had been in my plans from the start to introduce some home-brew concepts (usually in the form of items) as the game continues. However, talk about the upcoming One D&D (essentially 6th edition) had me thinking about one aspect from 3.6 that I wanted to bring in: better critical hits. While 5th edition simplified the rules on critical hits from 3.5, they still don't seem that effective. Even though the player gets to roll two of the damage dice, it is still quite possible (likely even) that a "critical" can do less damage than a normal one.
For this reason, I'm bringing back my max damage rules for 19s and 20s on a d20. Basically, if the player rolls a 19 on an attack roll (as long as it indicates a hit), they do not need to roll the damage die as they automatically do the maximum damage allowed by that attack. If the player rolls a 20 (which is always a hit), they only need to roll the damage die (or dice) once as they add that value to the maximum damage allowed by that attack. Any additional damage (such as with sneak attack) is rolled as normal. This way, all critical attacks do more damage than a normal attack AND players get to celebrate when rolling a 19 as well as a 20. Note: I'm not aware of 5th edition rules that expand the die rolls that allow for a critical attack, but if there are some, I would expand the home-brew for those instances. Also, I only do this for player characters and NPC party members; monsters would have too great of an advantage (since there are more of them) if I used this rule for them, so they would follow the standard damage rules.
I'm hopeful that my players will like this change.