The thing is if he screws up, he won't be welcome at one major club - it was a long time after Chelsea before he came back to City. I think he's poor, and Chelsea was ludicrously bent, but he's now at a level in the ref ranking that there's a fair amount riding on it.
Geographical appointing isn't really workable. Otherwise some refs would be barred from many top games simply for living somewhere. I understand a few are always considered - Oliver doesn't do Newcastle, I think - and Dean rarely does a Merseyside club outside the derby. There are a lot of refs from the NW, and it would arguably be worse to have the same ref every fourth week.