that along with calculating entropy + byte for byte repetition checking + the percentage of how many times each byte character is in said file will go along way i think :)

This of course is a false assumption. There is no need nor reason why an encrypted file should be anything like random noise.

Consider the unbreakable encryption of the "one time pad", or in other words, a key with a length not smaller than the message to encrypt the message. Unless you have access to the key, your encrypted file can be anything but it can never be decrypted. There is absolutely no way you can discern a properly encrypted file from a corrupted file, since actually any string of characters can mean anything. It all depends on the content of the key.

If your encryted file shows certain characteristics, the lack of which indicate corruption, then the original encryption by definition was less secure.