Things aren't set in stone, this is an alpha release, probably even more of a demonstration of what can be done. I'm not really happy about the programmable/fixed situation, but it was the only way to cram all the functionality into the tiny program flash without writing separate drivers.
Right now I'm not sure if I really want to keep the programmable light levels. After all, it's very hard to see a difference between, let's say, 75% and 80%. What is so attractive about the programmable light is probably not the fine grained control over light levels, but the ability to arrange the modes in a preferred order. Maybe it would be better to offer a number of fixed modes spaced at reasonable levels (e.g. 1%, 5%, 15%, 30%, 50%, 75%, 100%, strobe, beacon, whatever), from which three can be chosen in any order and stored into the mode slots (and the others could still be made available through a special click sequence). I'd be happy to hear some opinions on this.
Edit: Mode switching through brown-out detection is not planned so far. This would depend on the specs of external components (namely, the buffer cap) and right now I'm trying to keep this dependent only on the micro controller used.