>>58696135Mega Lucario takes the most notable parts of Lucario's design (eye mask, head appendages, arms) and gives them notable changes. Even the head tendrils are a callback to a legendary from its region, and it influences a fur pattern that Lucario previously didn't have.
Zeraora's mega is only really distinguishable by color and extra tail. The horn and claws change is underwhelming by how small the change is, especially when it already looks that way when attacking in it's base form.