Subclassing is not only about technique but also about semantics. Once you start with that, I will also be doubtful if the method "doX" or "createY" or "findZ"

Subclassing is not only about technique but also about semantics. Once you start with that, I will also be doubtful if the method "doX" or "createY" or "findZ" will do what they promise or behave completely unexpected. That's why we try to follow liskov, and with your suggestion you are breaking this assumption/convention.