I'm not certain, but the reason the switch is on the back is probably because it keeps all the AC power (which can induce hum and noise) as far away from the sensitive front preamp gain stages as possible.
I have an F2B, but I suspect that the layout is similar to the F1X. The AC power comes in on the power cord, through the fuse, the power switch, then the transformer. All that stuff is on the back and everything else in there is DC powered (no induced hum). If you routed the power switch to the front panel, then the AC would pass close to the low level signal path.
I don't like that switch back there either. Since the chassis is short, I usually found that I had to reach in a long way to get to the switch, often between other components and at risk of pulling out some other wiring. I always left the power switch on, and was careful to turn off my power amp first (with its front panel switch) before turning off the entire rack with a power strip. As long as the power amp is off, you won't amplify the big thump that will occur when you power the preamp down. The power amp's input circuit will still be exposed to a big thump, but it shouldn't hurt it.
