Just my opinion, but Rothenburg, as pretty as it is, is more a photo-op daytrip destination than a place to spend the night. Yes, very pretty and nicely maintained--they did a good job repairing the extensive destruction from WWII bombings. BUT it is tour group central for that part of Germany, and, as a result, just about every business in the old town (Altstadt) is aimed at bus tour type visitors. Nothing wrong with doing bus tours if that is what works for you, but you do get a different vibe and type of experience in a town that caters to the large tour groups than one that does not. Some people do seem to enjoy the entertaining night watchman tour in Rothenburg--but I wouldn't consider it a "must do" that would take me there just for that.
There are other towns and smaller cities that, while they also get their share of tour groups, are not in existence solely to cater to those tour groups. Bamberg, Wurzburg, Coburg for three examples.
I would prefer Koblenz to Rothenburg o.d. Tauber.