You can find lots of references from the time of the repeal saying "this is a bad idea because this act was designed to prevent banks screwing around in the way that caused the Great Depression, and the inevitable result of repealing it will be to cause a similar problem".

Then you can look at the CDO crisis less than ten years later and talk about correlation not being causation until you're blue in the face.

Here's another prediction: the destruction of the CFSB will lead to anti-consumer behavior at large banks.

The bailouts certainly would have been easier if retail and investment banking had been separate. With the current state the investment bankers can hold everyone hostage because they may also blow up regular bank accounts.