The Legendary Super Saiyan form erupts from underneath the flesh of his previous form. It is implied that Broly must release some of his power in order to maintain his body's physical stability, meaning that there initially is a limit to how much his power level can increase at one time.
I think there's a lot of difference between a rip off and something that draws inspiration from something as no one man can own a concept of something. If that were the case then everything in the world is basically just a rip off of something Superman included
I couldn't agree more. Having similar powers doesn't make character a rip-off.
If that was a case then Superman is Hugo Danner rip-off, Batman is Zorro rip-off, X-Men are Doom Patrol rip-offs, Cyclops is Comet rip-off, etc.