I'm with Meera and Davidfor on this one--I love the ability to quickly adjust the brightness on my Aura HD by swiping next to the bezel-- use it frequently. I wouldn't want a light sensor--have a Voyage with that and can't seemto get it to work for me. Have ended up turning it off.
I would like the ability to quickly adjust font sizes on my Kobo as well though. Maybe with an up/down swipe on the right side of the bezel.
Would be nice if these were user defined options and Kobo gave you the choice of whether you wanted to activate them or not.