im pretty sure there are gonna be cries for blind pick in ranked after this purely for the sake of not having it yet in ranked while normal does have both modes.
The point of having normal game draft mode is to be able to practice for the real ranked stuff and to make picking and counterpicking more important. Strategy is more important.
For example: Ryze as a Veigar counterpick, Lee Sin as an Akali counter, etc.
So, that doesn't work either way.
It is a good idea to implement a more complex mode in normals whilst implementing a more luck-based mode in ranked where losses actually matter is herpaderp.