Wow - it's interesting how this story continues to grow ('derailed the entire company'? seriously?).
He didn't let the Sonic X-Treme team use a
level editor. If the completion of your game (after two years of development) depends on someone else's level editor, then you're doing something seriously wrong.
Mike Wallis:
"they shipped us a NiGHTS editor, a level-based editor and our designers where familiarizing themselves with that, and after about two-weeks, Yuji Naka who was the designer of NiGHTS, and one of the original SonicTeam, had said "No"."
They
never had access to the X-Treme engine.
It's seriously amazing that people are so willing to forgive the atrocious development of Sonic X-Treme and place all of the blame on Yuji Naka, who wasn't even involved in it.