Any love for Kutna Hora?

Not a good idea for two reasons: First: if you go to Kutna Hora you want to see among others Silver Mine.
Second: Kutna Hora is not on the way from Prague to Cesky Krumlov. By public transport you would have to come back to Prague to go to Cesky Krumlov. Even if you drive the fastest way from K.H. to C.K. would be via Prague.

well yes I do have a love for Kutna Hora and have visited there several times bus as llja says it is the wrong direction for a stop off on the way to CK.Fine if you want to make a separate day trip but not as a stop off.
An alternative might be the small Hussite town of Tabor, very interesting place and certainly in the direction you want to go.

Kutna Hora is well worth a visit, but not as a stop between Krumlov and Prague. It is too much of a diversion. Stop in Tabor instead, and make sure to visit the Hussite Museum on the town square. It is one of the best museums in the entire Czech Republic.

As for Kutna Hora, it is also well worth a visit. Make sure you visit the Church of the Assumption of Our Lady and St. John the Baptist, across the road from the bone church. Most tourists overlook it and they miss a real treat.

In Tabor there is also a really nice medieval museum inside the tower on the edge of the old town, really good .You can also do a tour of the underground passages in the town. Must say Tabor has been one of the friendliest places I have visited in the Czech republic, not a great deal of english speaking tourists but everyone was very nice and friendly towards us, a real joy of a place to visit.