Please do not go back to Old Leblanc Riot, it is NOT FUN to play against.
Old Leblanc was the most bullshit thing to have ever existed in the game since season 3 Kassadin. A hyper mobile assassin with point and click burst is not fun to play against. Nor is it fair. It just feels like bullshit thats it. Its like playing against a super fed Veigar who has a ton of jumps and ults every 10-15 seconds.
Its bullshit frustrating gameplay. If anything I'd do a mini/medium size rework where you remove her W for something more interesting fitting her thematic or her point and click Q. As they both make the kit impossible to balance and BS to play against.