Sasuke's plan isn't very well thought out. He really doesn't know what the Tailed Beasts are, and therefore thinks that simply killing them will get rid of them. Of all of the primary characters in the series, Sasuke has always been the least informed. He may be considered a genius, but he really doesn't know anything. This leads him to make rash decisions that end up having unintended consequences. For example, leaving the Village to pursue power, only to realize that his ultimate goal should be to become Hokage. killing Itachi, only to find out that Itachi was working on orders from the Village, Killing Danzo only to learn that his brother actually loved the village.