Because if every esoteric option was in the administrative control panel we’d need a 3-monitor system and a gig of server space to host the admin pages :).
I’m not so sure I agree that this is an esoteric option. I definately agree that every option can’t be catered to, but at the very least an option between “redirect to last page” or “redirect to profile page” should exist. The majority of times someone logs into a site they are not going to be modifying their profile settings, but rather accessing content they have access to as a registered user.
Anyway, that aside, I’m modifying the first $redirect_to assignment under the default: case – the rest I’ve left alone.