Without getting bogged down in specifics there's definitely a sense sometimes that laws and policies are set by people who rarely set foot outside London.
This isn't a disagreement, I'm just pointing out how great regionalism/federalism could be for the UK
The GLA is not a legislative body at all.
The mayor is responsible for transport and, uhh, that's about it.
p.s. FWIW I don't think you should be downvoted for this comment. You were right.