Uhh... somehow i doubt running water through a filter or taking it from a tap is gonna be an overkill difference while making okonomiyaki.
Tokyo is no diff from Osaka except perhaps in method, and local flavours.
But flour is flour, meat is meat, squid is squid and all the other trimmings you can add, i'm sure nationwide are available.
Obvious difference being the small subtleties, but Okayama, Osaka or Tokyo, all okonomiyaki tastes good to me, no matter how it's made.
Monjayaki, is something really really diff (okonomiyaki isn't that sticky for starters, lol)
So i wouldn't be so fast to shove them in the same boat.