@Tomaha: "I assume Rinascimento is only a simple variant".
No, it's not. The imbalance between powers is 0-4 in starting centers and 1-4 in starting units. Several powers just can't hope to win unless extremely unlikely lucky conditions are met, most of them can however hope to survive with some dignity till the endgame, although there are two or three (Siena, France, Pisa) that have very difficult to achieve even that and are almost invariably destroyed early on.
These problems may be attributed to poor game design or to a different concept of game design, debatable. It is still a popular variant for some reason and I have played it several times in the last few months (luckily always getting playable powers). I'd say the powers can be sorted as follows:
1. Venice: the big guy, nice starting corner position, many neutrals to grab and strong potential to control around 1/3 of the board (further advance may be hindered by stop the leader alliances, forcing a draw).
2. Genoa, Naples and the Pope: strong but with various issues that compensate. Very playable anyhow.
3. Milan, Savoy and Firenze: weak but still playable. Turkey may also be in this category, even if it begins with no centers and is bound to lose at least one unit in the first year.
4. Siena, France, Pisa and Ferrara: almost designed to lose. Exceptionally, in my experience, Ferrara and France may survive and even begin to thrive in their minimalist modesty, but always well behind the level development of the powers of category 1 and 2. It's possible I guess that the same may happen to Pisa. Siena has no chance unless it deceives and stabs a very gullible Firenze.
The game typically ends in draw, largely because of stalemate lines being favored by those silly Appenine impassables and because of stop-the-leader alliances. Also lots of drawers over here.