The following is part of a comment I posted on another blog, Imagining History, but is a topic I will return to in the future here so I wanted to post it.
I feel that those of us outside of mainstream economics spend to much time teaching things we have already rejected. Part of this is necessary to keep our paychecks but part of it we do so we can feel superior to close minded mainstream economists. At the introductory level I think we need to do more of teaching Marxism as what is "right", not as an alternative theory.
I feel that in many heterodox economics classes that I have taken, my education has suffered because a lot of focus and time has been given to the mainstream. If I thought that a thorough understanding of mainstream economics was worth while for me, then I would take a mainstream class, or attend grad school in a mainstream department for than matter. The more time we spend trying to thoroughly understand the mainstream the less time there is to study alternatives.
As a teacher, you have the power to have studied and rejected the mainstream ahead of time, so your students do not need to take the time to struggle with this in their first semester of economic history. If you believe the heterodox perspective holds more merit then you should teach only that. Otherwise you are placing heterodox theory at a natural disadvantage because mainstream courses do not take the time to go beyond a bare mention of Marx, Keynes, Kafka, etc.
It is within your job, hell it is your duty as an instructor to teach your students what YOU feel is the best course you can offer on economic history, using the best methodological approach, from your point of view that is.
If this means not doing the mainstream justice, so that you can spend the limited time that you have with your students giving a more thorough (non rigorous)course in economic history from a heterodox perspective, I would encourage you to do so. Plurality has many benefits, but within the confines of a single semester, in an undergraduate course, I would think you are better off teaching history from the perspective that you prefer.
That is unless you want the course to be a methodological survey of economic histories....which would a fantastic course but....maybe not at the undergraduate level, and the university may question why you have an s on the end of the word history in your course description.
As non-mainstream economists, beyond a basic understanding of the mainstream, why study in depth something that we think is "wrong"? We have rejected the mainstream without learning its nuances, certainly learning the finer points within the any theory just makes its contradictions come even more to the surface? (To be fair this point is as true regarding Marxism as it is any other theory)
There are only so many hours in the day (even fewer for those of us who blog). I would encourage you to spend the few you have with your students teaching things that they cannot get from any cookie cutter text on economic history.