I like the sound of using double-click to cycle between modes. With Photon Freedoms I find it hard to switch modes.
Power save mode sounds good. My Freedom is stiff enough that it doesn't turn on accidentally, but this is a real concern for other people.
I'm not sure I see the point of Lock mode. It seems really esoteric. And maybe a bit dangerous if an accidental double-click from off makes it hard to turn off. If this mode is provided I would put it after the blinking and SOS modes.
I like signal mode. I think it's more useful than the blinking modes. Is there a confusion between "keep clicking for signal mode" and the double-click to switch modes? From off, double-click should be perminant mode, then double-click again should cycle between modes, so how does it know you want signal mode?
I see the Photon blinking modes as basically gimmicks. I've never used them. It might help if they are documented to give long battery life (ie say how long). It might also help if the frequency could be continuously adjustable, eg if press-and-hold changed the blink speed instead of brightness in these modes. Ideally you should be able to use it as a strobe to eg, "freeze" rotating fans. That would be cool.
In any case, I see no point in press-and-hold doing nothing in blinking modes. It should at least change brightness. Ideally a dim slow blink will give awesome battery life - like years, enough to use it as a locator eg when attached to your keys.
If you ever do a light that's bright enough that the strobe can be used offensively, then that strobe should be easy to get to. No more than 2 double-clicks from off. It would be needed more urgently than SOS.
I'm not sure how important the SOS mode is in practice. Obviously it's going to be used rarely, if ever, but do you even have reports of it helping people in emergencies? Anyway I guess it doesn't cost much to include it somewhere and it probably helps marketting.
It's tempting to make SOS easy to find/get to because when you need it you really need it, but unless you compromise other features it's going to be at least 2 double-clicks away, and that's far enough that it's effectively hidden except from people who know it's there. So you might as well put it last or near-last in the sequence.
I don't understand what BR1/BR2 modes are.
The standard operations of double-click to change modes, and single-click for off, and press-and-hold to tune current mode for brightness or speed, I think make it simple enough to support a lot of modes. It sounds cool.