I don't see Brussels becoming a religious city state.
-One alternative would be that Brussels is moved to mercantile (which at least makes some sense) and that whatever the peach colored replacement or Marrakesh is, is moved to religious.
-Another is that Florence is changed to religious and its colour changed. This has never happend before, but it has also never been necessary before because no previous change has led to a color/type conflict. And it is not like it would be a lot of work to change the color of a CS.
They actually did have multiple city states with the same colour type in Vanilla, but as they shuffled things about in Gods & Kings they changed them all. So far though, the only case where a city state has been given a known colour-type combination has been when it's been a replacement, so giving Florence religious and cyan would be a bit odd, but that could be a case of a black and white painted horse rather than a zebra. I don't think that's what would have happened though.
They don't seem to just change colours either. They have in the past used known city states as replacements (Lhasa and Budapest for Vienna and Edinburgh), but they've never just changed a city states colour. In the case that they used them as replacements they were the same type as those that they replaced (Lhasa would subsequently go from Cultured to Religious, but that's another story all together), but with a data set of two it could just be that it was more luck than anything else that they picked those two. It is entirely possible that Brussels could be used as a replacement for Marrakesh and a new religious city state may have been added instead, hence making the totals 12-12-12-8-8.
I believe Budapest/Bucharest (which ever) changed it's colour without changing type as it replaced Edinburgh.
Question, is there anything stopping devs from simply balacing out each type? why do Militaristic and Religious have to have few city states less than the other three?
It was Budapest.
I think they have them different for balance reasons as I'm pretty sure that city states are just added randomly, not weighted by their type. They could be balancing out their types all to 12, but I can't see it as we just haven't see enough new city states of the other types, by this point we should have seen most of them, having another 8 coming is a little bit of a stretch to think at this point. Statistically speaking if that were the case we'd have seen more by now.
Or they could have added one less cultured city state and one more different religious city state to escape the issue entirely. So it is still not necessary to force a colour change with this expansion.
I am baffled. Menzies, save us!
We have to think of it from their side, what did they decide? Whilst we're working the other way, they wouldn't have gotten the end and gone: "Oh, we've added too many cultural city states, better change some others", that's just not what would be done, if it were they would have just removed the last couple they added. Instead it's obvious that if they are indeed going for 12-12-12-8-8 they clearly made the decision to add more cultural and use a pair of cultural city states elsewhere. I don't know, maybe they came up with some primo cultural city state names and just wanted to use them, who knows. Maybe someone just some "give me some of that Kiev" over dinner, whilst someone else joked about adding Kyzyl, and someone thought that they wanted them in, I don't know...
Anyhow, there are various options for what has happened. I particularly like the idea that Brussels could have been used as the replacement for Marrakesh (so, it became a Peach Mercantile city state) and another Religious city state could have been added. But it could also be that Brussels has been changed to religious. I doubt that it's Florence or Bucharest, as it would probably require them changing more than just their type without it being a replacement, so I don't really see that happening. Oh well, let's see what happens.
Brussels can't be made to be Mercantile. We know it is still Light Blue. Zanzibar is also confirmed as a Light Blue Mercantile city-state. Brussels and Zanzibar can't both be Light Blue Mercantile.
It could be used as the replacement for Marrakesh though, which would make it Peach and Mercantile.
There is another option that has been done before as well, there just might not be a replacement for Marrakesh at all, and a cultured city state may be changed to Mercantile, but that would also work for Bucharest based on colours. I can't see Bucharest being made into a Mercantile city state from Cultured though...