How to balance Leblanc
Make her exactly like she was mid of season 2.
Work from there but that should be a good starting point.
Yes this means that a perfectly timed combo can result in a 6 second silence. No you are never going to manage to do that yourself but you might be able to manage a 5 second one.
Yes this means she is back to being a really effective lane bully but was well known for falling off late game.
Did I mention 2 secodns instead of 1.5 to get out of the chain? The fact that W would travel faster then Q? No DFG still since this is a LB revert not a item revert.