Is The Flash "potentially" the most powerful Justice League member?

Nope. Aside from Superman, there are those who can out think and out fight the Flash without being super fast. Batman and Wonder Woman for example.

Well now with the new show that s out t looks like it, I mean his powers are still growing and he is already able to time travel. Though superman is pretty much the most cheap superhero ever because it s basically no challenge to him, and yes I get that he has a weekness; Kryptonite. but still he is pretty much unbeatable, and we won t truly know till the batman V superman movie, but then again with flashes speed he could definitely hold his own. Until the batman V superman movie we won t know for sure but my opinion is that for sure yes he has the potential, but weather or not he is will be answered soon.