Tim, in a S15 you can easily overclocking it to do 33TH and oficially it just do 28TH its a big difference and Bitmain dont allow people to do it with web interface.
I agree that's a huge issue.. unfortunately there is no S15 firmware that allows for ssh, we should at least have the choice to use ssh if needed.
I don't have any S15 yet, might want to contact Alex as it seems he's got ssh working on his S15?
https://www.youtube.com/watch?v=UJv6rrUNU60.