I carry in my pocket a StreamLight Stylus Pro, which is the pen-shape style AAA x 2 with a clip.
I just clip it in my khaki pants and it sits nice and slim.
Carrying my AA lights I find them too thick...Also the Fenix E01 is a great little pocket light and its AAA.
These lights are just for emergencies due to small size, if you want a dedicated light you plan to use all the time, then you need something bigger...but I think AAA is fine for what I occasionally use an EDC light for.
Then when I go walking around at night I get my 2xAA light, dedicated for that task, I cant EDC that around all day.