Random idea I can't get off my mind lately:
1: Maximum damage.
2: Double damage.
3: Triple damage;
4: Special (depends on weapon, armor, etc).
Example: if your usual damage is 1d6+3, maximum damage is 9, double damage is 2d6+6* (Average 13), triple damage is 3d6+9* (average 19.5).
*OR just roll 1d6+3 and multiply by two or three.
A super-critical is achieved when you crit and beat the target AC by 10 or more, or when you have advantage an roll 20 on both dice. In some circumstances, all your crits will be super-crits, while in others none will (however, you can reach crits through combos - see my next post).
I thought of this as a rule for my Dark Fantasy Basic but you can obviously use for D&D 5e, etc. Notice that "maximum damage" result is slightly worse than the usual 5e crit... but it kinda FEELS better IMO, and is one less roll.
I just like crits! They are exciting, fun and a great way of differentiating weapons and characters, since only a few hits will be crits. It also gives you that "urgency" - the fight may suddenly take a sharp turn for the better or worse...
However, I get bored by long tables and dislike stopping combats to check complex rules/charts.
Super-crits are intuitive and significant. "Special" results - you can put whatever you want there, but should be very significant, and maybe IN ADDITION to triple damage - will happen less than 2% of the time. THEN you can use a table or complex rules. Almost 99% of the time, things will be straightforward.
Notice that this crits will make the difference between creatures of different HD/CR more significant. A level 10 fighter will be very likely to destroy one orc per critical hit in 5e - or even an ogre (4+1 HD) in B/X or DFB.
Likewise, heroes must think twice before attacking something that is out of their league. In 5e, this means the need for "minions" for high-CR foes is made a bit less relevant.
Well, that's it for now.