Yikes. How are we supposed to construct the floating cities? Mining Venus is out of the question with non sci-fi tech, even if all we wanted was to make, say, concrete.
If something happens to the floating cities, the "fall" would be a horrendous fate.
Temperature isn't "nice", would still be around 160F high up.
Importing materials... at that point why not just make space stations?
An enclosed bubble of Earth atmosphere would literally float in Venus's atmosphere with about 6x as much lifting force as hydrogen has in Earth atmosphere or 10x as much as helium. As long as you can breathe, you don't fall (though "sink" is probably a better word for it than "fall").
If something happens to the floating cities, the "fall" would be a horrendous fate.
Temperature isn't "nice", would still be around 160F high up.
Importing materials... at that point why not just make space stations?
No water.