He invented modern distortion. He hot-rodded his marshalls to create a tone no one had ever heard before. It literally changed the rock music industry. It also changed the way amps were created for the next 30 years but that’s an understatement because it didn’t just change equipment, It changed music.
On top of that his style of playing and difficult techniques literally went perfectly with the new distortion sound he created. Everything he did was absolutely perfect. And every rock guitarist after was influenced by it in some way. I really think his distortion and the production techniques Van Halen used along side it pushed the wall of sound that had been used for 20+ years to an entirely new level.