I must be an odd duck. My L1 switch usage is approximately 60% twist-low, 30% twist-high, and 10% momentary high or low. When my light comes on, it stays on while I accomplish what I need to do, typically with both hands. This characterizes my in-house/nighttime application for this light.
Since I overwhelmingly use a one-hand twist to activate, I take special care to insure that my tailcap O-ring is clean and regularly lubricated with a low-viscosity synthetic lubricant. As a result, the twist action is smooth and easy.
For my usage, the low-high progression is appropriate. Now, could I see a benefit to a clickie interface for low-high? Yes, I think so. But to make it KISS, the switching paradigm (as well as the internals) would have to be completely rethought. Here's what I see as an example of a "correct" two-stage clickie assuming that sequential multiclick activation of modes is undesirable.
1. Depress 75% of travel then release - to "clicktivate" low
2. Depress 95% of travel then release - to "clicktivate" high
What this means is that <75% of travel, you are in momentary LOW, after the 75% click point, if released, you are on constant on LOW.
From here, if you push again to 75% and click and release, you go OFF, never having accessed HIGH.
However, if you continue pushing the switch to 95% travel, at that click point you are now in constant on HIGH never having gone OFF.
Now here's the novel pattern. At this point, click to 75% to reactivate constant LOW or click to 95% to click off constant HIGH.
And there you have it, I think. An intuitive click interface, single depression to activate and deactivate either high or low modes. Because it is a click switch, it would require tactile feedback which implies that that the mechanical design must contribute that action. Perhaps a concentric, serial click mechanism. However, the actual switching could be electronic in nature.
Wilkey