You have only 2 weeks including arrival & departure days, so 12 days on the ground. Without knowing your interests, it's hard to advise what your priorities should be, but I do think your plan is a little on the rushed side.
Ravenna is great if you are seriously into the Byzantine period. But why 2 nights in Monterosso? (And do you mean the Monterosso in the province of Ancona, south of Ravenna and San Marino? There is another Monterosso in the north, between Venice and Verona -- and one in Sicily, for that matter.) Similarly, why 5 nights in Positano but only 1 in Rome?
If you really don't care for cities, then you may want to eliminate Florence. Two things I would not change are (a) spending at least 2 nights in Venice upon arrival so you can shake off the jetlag, and (b) staying in Rome the night before your flight so you will not be at the mercy of any transport disruptions trying to travel to the airport from Positano or elsewhere.