I'm not sure about MVD, but I would say flying out of AEP (the domestic airport of BsAs) is pretty easy and was a 5-10 minute cab ride for us from Palermo. Also, I'm not sure if this is possible, but perhaps you could then fly from IGR to MDZ and go to Chile that way?

Iguazu Falls is pretty amazing, but then again so is Buenos Aires. However, if you're seeing all cities the rest of the time, perhaps spending time at an amazing natural wonder is a great idea.