Well, as someone would say, I know what I want, but not how to do it
More seriously, finding UU and UB is difficult in my opinion, because they are a lot of thing to consider. A lot of country have more than one epoch where they were distinctive (like Germany, England, rance, America), some had strength difficult to cater into unit or batiment (the Stock exchange is a prime example : I see what they want to emphatize, but apart from London I don't think they are any kind of real financial place in British kingdom), and in some case it's easy to go into overkill.
The example of France is for me typical : one of the more flavorful period of France history is revolution. But it's very hard to translate into Civ term : they had a frightful army (even before Napoleon), but that was because France were a big country and strated to conscript, not because the units themselves had something outstanding ; the administration changed completely, but a corthouse UB would appear much too soon ; and the leader are really obscure for non-french (and even a lot of french ; St Just and Robespierre are not widely known, in addition to be in some aspect about as evil as possible). The best thing I could see would be a prefecture UB with either added culture (because the France nationalism began to form at this moment), or added conscript capability, but what building would it replace ? Courthouse are much too soon, jail would feel about as akward as India UB.
The choice in BTS is in general rather decent, and in some case very good. Some are weak, the french musketeer is a prime example , but thing like bowman (and the whole babylonian / sumerian distinction that is pretty hard to do), camel archer (the history freak side of me would have taken the Mamelouk, but they are not exactly well-known, and on top of that not proeminent for a lot of time. They would fit with Saladin, however), but all in all they are in my opinion at least decent.