how exactly does one play venice? which baseline AI behaviors are failing with them? which special strategies would be needed?
Venice is probably the most basic warmonger to play, but is dependent on initial success. You build a few warriors and archers yourself, buy a city-state or two to bulk up, and then DoW your most vulnerable neighbors and never stop getting new cities after. It gets even easier to spam more units with landsknechts since you can batter cities with abandon as you rake in the gold. Should be easier to do now since you don't have to look at your puppets what with happiness not being an issue.
Not exactly, i used to play Tourism Venice with great success, having only 6 or 7 cities on Standard size. So you do not need to be Hitler really. At least not every time.
First of all Progrees for Venice is totally useless, should not be taken at all. Most of times it should be Authority (free Settler first!), but Tradition -> Tourism is okay.
Authority play:
1) Venice should probably take some military tech like Horseman, than rush into Trade (taking Trade asap works, but my experience says that it should not be taken as 3rd tech cause you need time for City-States to get more units)
2) Take Trade as your 4th/5th tech, at the same time get a free Settler from Authority and buy two City-States with their army. Better to buy closest ones, but depends on what resources and army they have, 2 additional free Spearmen worth buying a more distant City-State
3) While waiting for City-States - build army (Horsemen+Archers)
4) Once free units are taken (or even few turns before it) declare a war on your neighbour. Better to DOW the neighbour that settles between your City-States and you
5) Capture him and go for the next one if necessary
6) Vinice Merchants are good for diplo victory, so you actually do not need to buy all possible City-States. Also generic Science play is also good.
Tradition-->Tourism play:
1) Rush Pyramids asap (very high priority!)
2) Get free Settler from Pyramids+free Settler from Trade
3) Capture your neighbour (3-4 cities)
4) Stop and play Tourism as usual
5) Dont forget to build the building that gives +2 tourism from villages and prioritise them.
6) Might be worth to take 1-2 more City-States to get more Great Merchants in future, they give a lot of tourism (plant them in your capital, culture converts into tourism in future)
One thing that is right for sure is that Venice should take advantage of free units and that it does not need to build Settlers (others can build those cities for you!). Even human on Deity can easily get largest army on the world early on.