I think you have to hold a second class physical to be a controller. I know for sure controllers don't have stricter standards than pilots as I used to work in an ATC facility and know first hand.
ATC as a fall back isn't the greatest for a couple of reasons. One being the age limit is either 30 or 35, I forget, but over that age you would be too old to get hired as a controller. Also, ATC is a one time shot. If you got hired as a controller and then left to get back into flying (like I did), that would be it. You'd be done with ATC. It's not the sort of job where you work it for a while and quit for a while and then go back.
However, if you really are considering a career as a controller, along with one as a pilot, I can't fault you for majoring in ATC. You'd have a few years to make up your mind on which way go after you graduate and can make a more informed decision.