The general consensus with Venice is to go Tradition (which is the general consensus for just about every nation it seems.) I agree with consensus, as I've tried both ways and Tradition seems to work pretty well. The one thing I have to say though, is that the first time I played them (in which I got Liberty), I had about 10 to 12 cities near mid-late game, and my cities were pretty much crapping out merchants. I was literally getting merchants about every other turn near the end. I was actually doing multiplayer and me and my friend were in a diplomacy battle as he desperately tried to steal delegates from me to keep me from winning. He was simply unable to keep up, because of all the trade missions I was doing. On tradition files where I have had 4 or 5 cities with them, my cities fluorish, but I did not receive 1/4 of the great merchants I received when I had 10-12 cities. My rationale for why this happened, is that if you have more cities, you have more markets, banks and stock exchanges to place specialists in, and thus more great merchants appear, provided that you have the food to sustain them. Basically more cities = more great people, of course if you have enough food to sustain specialists as I said before. Which is not usually that much of a problem with granaries, hospitals, and that Freedom tenet that decreases specialist food consumption by one half.