Avira, my saying that Rav Natrunai Gaon refutes the Maharsha is no worse than you saying that the Rambam refutes Rav Hirsch (which by the way I don’t think he does).
I have plenty in my head besides Nathan Slifkin and blogs. I probably know more than you. (Haven’t you seen my screen name? 😉
The fact the snake issue is a drosho doesn’t change anything. We are not obligated to accept Chazal’s non-Halachic droshos. As Rav Shmuel bar Chofni Gaon says (quoted in Radak, Shmuel Alef 28 ): “Even though it would appear from the words of Chazal that…these words cannot be accepted when contradicted by שכל,” and there, too, the reference is to a non-Halachic drosho.
Now, it is true that on today’s maps Bovel is very slightly north of Eretz Yisroel (under one degree of latitude), but in Chazal’s times they did not have modern maps. I’m not even sure Chazal had access to any maps at all. And every map that did exist then contradicted every other map. Moreover, most reconstructions of Greek and Roman maps have Babylon SOUTH of Eretz Yisroel, so of course Chazal had to bring a posuk. The fact you can show me that on a modern map Bovel is very slightly north is entirely irrelevant.