1.) Instant access to turbo
2.) Instant access to moonlight
3.) A way to disable mode memory by ramping from moonlight to low (severely lacking in many lights)
4.) Strobe should be a hidden mode - personally never found a real life use for it
5.) Moonlight, low, medium, high, turbo
Depends on the light .
Two mode keychain light / low high
I like the ability to on the fly change any mode into anything I want it to be . Old Archeon driver is the closest thing I’ve ever seen to it . Downside was it was two modes fully programmable and sos strobe . Upside is you could just shut off the light and it would start in the first mode you just set ,skipping the sos / strobe ..... i’d Make it a three mode and drop or hide the flashy stuff . << perfect .Simple ... easy to learn and change in seconds .
Not quite sure what to vote here. For my own use, I really like a UI such as ZL or AT uses with direct access to lowest, highest and memory/middle mode. Anduril fits here as well. For more of an emergency light (first responder, structural fire fighting, tactical, etc) I want simpler- maybe 1 mode or low-high. And a general purpose light for loaning or family use? Well the L-M-H simple UI is hard to best….
Love the magnetic control rings for smaller lights
1 mode for when I'm out in the middle of nowhere doing beamshots at night.. If I hit that button 1 or 100 times, I know it will have 1000 lumens each and every time, and not accidentally hit a progammable mode. When your life depends on a flashlight, you don't want to have programmable modes.
2 modes could be okay for a thrower. High Low
4 modes for most other instances.
Ramping is fine as well, but not on every light.
Perfect?
That would be ON-OFF
Always comes on in correct mode and never needs re flashing.
Doesn’t need a manual or grandkid to explain it to Gramps
With protected battery does not need LVP, when it dims Recharge it, if it shuts off-Recharge it.
Perfect 
Programmable all the way. If you program your light yourself, you can program to whatever way you want it to behave. Single mode? Can do. 3 modes? You got it. Blinky modes? Pick how you want to access them. Ramping? Sure, why not. More options is ALWAYS good, you can just not use them and program your UI to not feature them
Of course, you need a UI suite that gives you all these options to pick from, but that’s a given for anyone that ain’t a muggle.
I voted other. Could have voted programmable or 4 mode just about as well. As others have stated: Instant access to moonlight and turbo along with a memory works well for me. Love Andruil. However, not sure appropriate for gifting. Thrunite and AT do a good job with UI and I very much can live with those. Different lights different needs so Andruil wins. However, Something like the Manker or AT lights with the adjustable moonlight really is preferable but I think that is a hardware and UI issue.
I just saw this on Simon’s AX Convoy store, for the ramping M3-C mode selection / UI. I think this is pretty close to perfect for me. Simple and nice options. From the listing
Mode operation instructions:
1.click the button ——> flashlight is turned on with last brightness ——> press the button,brightness ramping up ——> release and press the button again,brightness ramping down
2.flashlight off, press the button ——> moonlight mode 0.01A (0.2%) [This brightness will not be remembered]
3.flashlight on or off, 2-click the button ——> turbo 100%
4.flashlight off,3-click the button ——> strobe
5.flashlight off,4-click the button ——> tactical mode, only 100% ,4-click the button again to quit tactical mode.
6.flashlight off,5-click the button ——> voltage detection (* means “flash” , * pause* means 3.7V, )
7.flashlight off,6-click the button ——> normal ramping mode switch to 4modes 1–10–40–100
8.flashlight off,10-click the button ——> Lock mode,The flashlight will flash once under any operation, which means the flashlight is locked.10-click the button again to quit lock mode,Please note that this is the only way to unlock.
I’ve never used strobe. Never will.
I think a bullet will call the attention
of the assailant the most.
I find the SOS important. For a car or for a boat.
Never being stranded in any of the two at night,
but it can happen in the boondocks.
So Hi-Low-SOS.
Cheers.
+1
Despite my attempts to make a “universal” interface, I think the UI really needs to be tailored to each light… or at least, each category of light. Change the hardware, and the “best” interface changes too.