On a flip side you can get models that do too much. At one point I had a method on a model that, in order to get data into correct format, just went and rendered a [Django] template. It came to that naturally, the line is thin, and I now prefer to err on the side of models doing too little.

> it's the part of the Operation to both decide what to show and also get it in the correct format to show

Did you mean Views, not Operations, here? Or maybe I'm missing something.