Frankfurt to Munich by train - the scenery!

(1) via Nürnberg: Frankfurt - Würzburg is nice; the line cuts through the Spessart forest and runs alongside the Main river for a while (right side). Würzburg - Nürnberg is ok if nothing special, Nürnberg - München is simply boring since much of the high speed line is fenced off for noise protection. (2) Frankfurt - Mannheim - Stuttgart - München is boring all the way. Moreover, due to the reconstruction of the Stuttgart station and the Stuttgart - Ulm line, trains are prone to delays currently.

I concur that going via Nürnberg is a little more scenic... but don't expect to be blown away. Unless they've completed the update since I last rode the line about two and half years ago, the portion through the Spessart mountains runs fairly slowly over tracks that weren't built to take advantage of the speedy ICE trains. So, you get a close look at some of the towns, which although not really stunning, are at least fairly pleasent. I can't remember anything of particular interest that you can see between Nürnberg and Munich, unless getting a glimpse of the hop cultivation in the Hallertau region interests you.

Thank you both for your input. Mildly interesting is better than nothing so I will plan accordingly.

Mabe you could fit in an intermediate stop of two hours or so in Würzburg or Nürnberg.
If you decide on the latter, you might want to follow an itinerary I have described elsewhere:
https://community.ricksteves.com/travel-forum/germany/nuremberg-or-rothenburg
(scroll down to posting #7).

Unless they've completed the update since I last rode the line about two and half years ago, the portion through the Spessart mountains runs fairly slowly over tracks that weren't built to take advantage of the speedy ICE trains.

Basically it's still a line of 19th century. As you are saying, views are not exciting but fairly pleasant. In comparison, the same time span spent on the Frankfurt - Mannheim - Stuttgart route will be fairly dull.

Ohio I can live with. Thanks.