Is Toshi counting his original 4 solo albums before he even met Masaya as part of his solo work that he's leaving behind forever? I hope not. Yes, his original 4 solo albums were made at the time when he was pretending to be a rock star and it didn't make him happy ect. But really, that was the same thing he was going through with X-Japan at that time as well, and he's still continuing with X.
He shouldn't leave his first solo albums behind, because as far as I know, those songs were written by him, his desicion to make, noone was controlling him, he probably got on well with the Nighthawk members and other people he worked with, and from what I can tell listening to them, a lot of the songs in those albums have happy messages, so I really see no reason for him to abandon those first solo albums forever.