Sounds good, off to Germany again in Dec.
Did Vienna this year in July and Pisa this month.
I recommend 4-5 nights in Vienna if you like art, opera, building, culture. Same for Rome, definitely 4-5 nights.
Berlign same I would think. Hamburg 2. Pisa 1. I stayed in a hotel 100m from the tower. Venice, 1 night, I went form Croatia.
This is train from Rome to Pisa. Milan is dull yet spent 2 nights there ge ton roof of Doumo.