This is the same argument raised by Colander, Holt and Rosser, that there is no mainstream and that the cutting edge of the profession is moving away from any established consensus. It is problematic for many reasons /1
The fatal challenge to heterodox economics is that there isn't actually orthodox economics.
Just take a few recent Nobels: behavioral, information failure, institutions, bubbles, financial fragility, labor monopsony (sort of), Schumpeterian creative destruction, etc.
Not to mention RCTs which are emblematic of how much economic research is empirical and only lightly if at all structural.
The real difference is methods. Heterodox economics is an avowedly political project not a social scientific effort to better understand the world. And I have nothing against political projects just shouldn't confuse the two.