Also, Yahoo! Woe!
To me, the most significant aspect of Shadal's identifying Shifrah and Puah as non-Israelite is that this makes them the first Chasidei Umot ha-Olam. Not only that, but it goes a long way to justify the collective punishment of the Egyptian people during the Ten Plagues. As Shadal later comments (on Exod. 9:27), "If they [the entire people] had not been at fault, they would have tried to divert his [Pharaoh's] anger from its destructive goal, but they said nothing to him. Instead, they agreed with him at once, and 'they' (not Pharaoh) 'set up over that (people) commissioners of levy' (Exod. 1:11). Now we see that the midwives, for all their weakness, did not do what Pharaoh had commanded them, nor did he punish them. How much more so could the entire people have annulled his decrees or softened them."
Interestingly, even R. Yaakov Kamenetsky in his Emes L'Yaakov mentions that any name that has 3 of the 4 letters of the name Pharaoh is probably Egyptian. (Shifra, Puah)