Kanzenshuu

Piccolo certainly didn't train. Babidi told Dabura to "take out the weak ones", and who went? Kibito, Kuririn, and Piccolo.
Pui Pui was stronger than Kaioushin, based on the fact that he said they needed to gang up on Pui Pui, yet base Vegeta was stronger than Pui Pui. At the Budoukai, Piccolo said ...

You are mistaking the regular ssj state with the full power ssj state. Ussj and Ussj2 are higher states of the ssj1 state that increase power at the expense of speed. Essentially a flawed form. Fpssj is the utmost max of the ssj1 state. As such it is the mastered form, you could say a perfected form ...

Well basically the way one can describe his ssj forms, are ssj, ussj. and lssj. Lssj is when he turns green. What the legendary super saiyan form is, its ussj, only w/o the minus to speed. Lss allows him to surpass normal ssj levels, thus him being the legandary super saiyan.