Munich--Venice--Rome MISSING ANYTHING?

You are probably doing it right, four days in each.

I really love Salzburg and it's an easy train ride from Munich (It's also counts as a German stop if you are using a rail pass, no need to add Austria or pay extra). If you get a chance, it's worth a look.

You might trade a day in Venice for an extra day in Rome. Venice is great but much smaller and easier to see the sights in less time. Rome has so much, any extra time there will not be wasted.

Mayra - Sounds like you've picked 3 cities that really interest you, so stick with them as your home bases and consider a few day trips. There are usually very cheap weekend train fares availalble to Salzburg (about 2 hours). Padua, Vicenza and Verona are all within an hour of Venice by train. Ostia Antica (similar to Pompeii) is an easy metro/local train ride from Rome. All are worthwhile.

There is certainly nothing wrong with your itinerary. But if it were me, I shorten Munich and Venice to 3 nights and Rome to 2 or 3, then fill out the rest with smaller towns along the way. But if you choose to stick with your plan, no doubt you will enjoy it.

You'll always miss something... all the more reason to return.