My ideal flashlight would be a headlamp. It is easier to hold a headlamp in your hand than to tie a flashlight to your noggin. It would use li-ion chemistry, probably 18650 size or possibly the AA equivalent.

A beam adjustable from wide to narrow (flood to throw) makes sense. It doesn't need a lot of lumens for most applications, although variable output is a useful feature. Using titanium for the body is a silly bling factor that only increases the cost IMHO. Aluminum is perfectly satisfactory.

The most important feature of any light is that it functions reliably, every time. Punch the button and it is on. Punch it again, and it is off.