i'm also looking for people that can confirm which other buildings need a level 5 city (in my test scenario i build most of the stuff in my capitol, which was level 5 after a few turns). until now i only can confirm that the shipyard needs a level 5 city (i had a harbor in a level 3 city, tooltip on shipyard was: "city not big enough")
i still need people that can tell me what buildings require the city to be level 5 i bet training grounds and military academy need this, but i would have to play a new game with a level 1 town and rush into those directions to confirm -.-
I forgot you can check the list of all possible buildings, so I don't think there's anything other than the shipyard, the fort and the magic tower which require level five and above. Except maybe for some special nodes, but I doubt that. I wasn't able to double check the shipyard either, because I forgot to make a new settlement on the coast. D:
Like the post above says, the Smithy is needed for Barracks.
yeah thanks i mixed that one up.
the problem on just listing all the buildings and looking at their prerequisite is that IF the building needs another building first and you haven't build it yet then you won't get the message "city not big enough".
e.g. if you don't have a harbor, and look at the shipyard it only says: need harbor first. when you then build the harbor and your city is still below level 5 only then you get the message "city not big enough".
so to figure out which building needs a level 5 city you must first build all the prerequisites before you can see if the next building in the tree needs a level 5 town :-/
Actually you can't build anything with a level 1 city, you have to wait for level 2 for your first building. So something like the Training Grounds isn't going to be available before the city is already at level five or higher.
I should probably edit this to say that a newly made Level 1 city will always get a farm, that's why you can't build anything with it immediately. If you capture a level one city it's possible for the farm to be destroyed when you claim it, which means you can pick another basic building to start with instead.