Same as the 4 or 5 above that think the UI is perfect as is, I would like to see zero changes.
As my non tactical light, the default medium 9 lumens is perfect for most tasks, a simple double click to make it a bit brighter, and I also love the 0.3 lumens which is perfect in the middle of the night (no more, no less), I also don't find I blind myself either as I just shield the lens when turning on, before triple clicking to get to low.
Can't say I'd ever want to use any ramping, too slow, too fiddly, and too complicated.
Only thing I'd ever like to see are:
Better efficiency.
1.2V capable driver (for 1 AA battery body).
Higher maximum (which will come in time with better LEDs).
User replaceable switch.