itinerary suggestions

Berlin plus Potsdam have more history related sites than Munich, e. g. Berlin Wall / GDR / Cold War related.

I agree with Mark. Spend more time in Berlin. Go to Sachsenhausen and Ravensbrück. Visit Track 17, go to the Olympic Stadium, the Wannsee Villa and the many museums in Berlin.

I think 4 days in Berlin is enough for a visit. Frankly I prefer Munich and Nuremberg. Berlin is the dirtiest big city I've ever seen in Germany, and while it has a lot to offer it's not my favorite.

KGC, OP's demand was history, not clean city. ;-)

You could spend weeks in Berlin and not tire of the history sights and sites. The various neighbourhoods are very different. Great food choices everywhere. Great walking adventures. My personal favourite things were:The Bibliothek memorial (Empty Library Square) at what is now Humbolt Uni. It's where the 1933 book burning took place. The Stasi Museum. The Rosenstrasse Statue , a memorial to the German women who demanded the release of their Jewish husbands. Seeing the Stolperstein (stumble stones ) everywhere. Wannsee Villa. Jewish Museum, Memorial to the Murdered Jews of Europe. A Reichstag Tour. The EastSide Wall. Art Island. Sachsenhausen Concentration camp: a pleasant train trip, a 20 min walk to the site, past suburban house from which the inhabitants must have seen lorries rumbling past, crammed with prisoners, 85 years ago.

So far, the the periods of German history referred to in this thread total roughly.... one. WW II (with pre-/post-war periods) is of course important, but alone, it shines only a small light on how Germany has evolved over the centuries.

Maybe that's all you wish to focus on. But an altered itinerary might provide options for exploring Germany during Ancient Rome's period of dominance, medieval times, Prussia, the Thirty Years' War, the Hanseatic period...

I agree with Russ. There's a lot of history in Germany, and not all of it is focused on World War II or the DDR. That said, if you are focused more on the 20th century, there is a lot of history in the places you have named, especially Nuremberg and Berlin.

I do think it would be more helpful if, instead of putting days, you list nights. Keep in mind that two nights in a place only equals one full day and possibly some time on either the arrival and departure day, but it's not going to be two full days. It looks like you have two nights in Nuremberg, so that will be affected. However, I think that that's probably plenty of time for Nuremberg unless you want to visit some of the places in the surrounding area like Regensburg, Bamberg, or Wurzburg.

Same with Berlin. You have four nights in Berlin, which is going to equal three full days, plus any time left over after you take the train there from Nuremberg, and whatever time you have on the day you fly home.

And also Munich although honestly, I don't think you need four nights in Munich. I enjoyed Munich, but there's not as much to see there as there is in places like Berlin and other cities. Of course, you may be planning to take some day trips from Munich to Dachau or Salzburg or other places in Bavaria, in which case then you might need more time.

If you are interested in German history, especially in WWII history, it's a great idea to stay in Nuremberg and Munich. You should at least spend one night in Nuremberg. In Nuremberg, you can visit the former Nazi Party Rally Grounds and the Memorium Nuremberg Trials (the reconstructed site in the Justizpalast), each of which requires at least half a day. Geschichte für Alle e.V. (literally "History for All") offers great history-related tours - also in English language. There is a lot more to see in Nuremberg, such as the WWII art bunkers, amazing churches, Albrecht Dürer's home and of course the Emperors' Castle (Kaiserburg). Geschichte für Alle e.V. literally "History for All") offers great history-related tours - also in English language.
Many (even Germans) don't know that NS history started in Munich in the 1920s. There you can visit the NS Documentation Center Munich. They offer free guided tours on the topic "Munich and National Socialism" each Sunday at 1 p.m. Their guides are historians and very good - very much recommended! Not far away you can visit the White Rose memorial exhibition and learn about their resistance against the 3rd Reich at the original site at Ludwig Maximilians University Munich. Also not far away is the "Feldherrnhalle" which played an important role in nazi propaganda. And of course, you probably want to visit the Dachau concentration camp memorial site.
From Munich you can also do day tours to Neuschwanstein castle (if you're intested) or to Berchtesgaden (in the middle of the Bavarian Alps), and at the same time a historic places with the remains of the "Berghof" on Obersalzberg [and the tea house "Eagle's Nest") which is popular with foreign visitors ;-)], with a great documentation center.
Rothenburg ob der Tauber is a nice place to visit if you want to take a break from all the dark history you will face in Nuremberg and Munich.
In Berlin I can recommend the Topography of Terror documentation center on the grounds of the former Gestapo, SS and Reich Security Main Office.
I think your itinerary is really great if you want to experience both history and beauty of our country (provided you will visit the Bavarian Alps, either by going to Neuschwanstein castle or to Berchtesgaden). I would consider an overnight stay (or more) in Berchtesgaden (fantastic landscape and the famous Lake Königssee) or Füssen (Neuschwanstein area) to also experience the amazing landscape of the Alps, and rather skip Rothenburg ob der Tauber, to be honest.

I agree with Russ. German history is much more than WWII / Cold War.

If that era is your focus, you could spend a month in Berlin alone. Way more interesting than Munich for history, both for 20th century and beyond.

And I would for sure skip Rothenburg and instead visit one of SO MANY other places.