I pity the MIT students that will waste so much of their intro course learning what is a vastly more complex language. There will be so many students that will struggle to learn python-specific topics that are irrelevant to learning the act of coding and may decide that CS and programming just aren't for them. Scheme is such a perfect language for this task because it puts so little between the student and the crucial experimentation phase that can instill a fascination/curiosity with programming. And now MIT students will miss out on that.