Leaving aside for the moment all the genuine concerns some people have expressed about this appointment, I am curious as to who would have made a "good appointment" Well certainly not anyone from the current gene pool that's for sure.
Personally I think a Nordie might be the least worst option. The last "insider" seemed like an excellent appointee -- look how that turned out. Any of the other options are going to be a still-bigger culture clash, both in the Guards and in the populace in general. Look at the daggers-drawn relationship with GSOC, for example, stuffed as it is with Brits and civvies.
But least worst might still be pretty bad.