The first one I heard was from G-dcast. The commentary came from Jason Lieberman, a man with cerebral palsy. It talked about how Moses felt unable to perform the tasks HaShem was describing. I had honestly never considered it that way. I always thought he just felt that better candidates existed and wanted HaShem to pick someone else.
The other point Lieberman made that I had never thought about before was that HaShem could have erased any problems Moses had. Now that it's been pointed out, I don't know how I didn't see it before. The fact that HaShem simply gave Moses an accommodation and sent him on his way is very powerful. It shows that disabilities are just challenges. It shows that we don't need superpowers to do HaShem's work. It also shows that we need to rely on each other. Where Moses was weak, Aaron was strong, and the two of them together were capable of more than either individual could ever accomplish.
The other podcast was Dvar Tzedek, from the American Jewish World Service, with commentary by Rachel Harcash (I may have this name wrong; I couldn't find it written, so I'm going with how it sounds). This does not appear in the podcast for Shemot, but rather, for Vaera. She also talks about how HaShem could have erased the impediment, but chose not to; however, she goes a slightly different way with it. She talks about how Moses had lived a life of privilege and had not been a slave. She also points out Aaron had experienced the exhausting work and the whips and the mind-numbing monotony of slavery. Her commentary raises the question: how could Moses speak for the people, when he had not experienced the injustices they suffered? By using Aaron as a translator, Moses's messages from HaShem would be colored by the collective experience.
I think this is a great question, and one I had never considered. For some reason, I had always had it in my head that Moses's speech impediment was a language barrier or a fluency problem that caused him to be difficult to understand. It seemed logical to me that he would have a hard time communicating with the Hebrews, if he'd learned to speak in the Palace. But this is a little different. The idea that Moses simply couldn't speak about the slavery experience, the idea that he felt unworthy to speak on behalf of those who were enslaved is fascinating. It's almost like he's saying that he'd feel inauthentic in that position. It also points out the difference between Moses and everybody else: he was the only one without the slave mentality. Perhaps that's the reason HaShem chose him; he had a mind that was open and capable of these ideas, while the others were somehow dulled by the endless work they had performed and the constant drain of persecution. HaShem needed them both.
