Eh, as someone who's been playing these games since 2005, I'm personally pretty burnt out on it. If they do something based far in the past (far enough that the look and layout could be massively different) then I'd be fine with more Kamurocho, but as it is I'm more on the side of feeling a bit over it.
Like you say, the place has been as much of a character in the Yakuza series as Kazuma... but now that Kazuma is over and done with, Kamurocho probably should be too. Or at least, there should be less focus on it.
It's not even a city, really; it's a district.
The city is Tokyo.
It'd be nice to see some story content moving across other areas of Tokyo, rather than acting like the entire universe revolves around this one single area.