Les Benzies leaving was a huge blow, but I'm certain that Dan leaving is the death knell for Rockstar as we knew them. Say what you will about the policy of putting all studios on one game simultaneously, rather than letting them make their own games like they used to, or the occasionally-pretentious/preachy writing, but at least the games were ambitious and strove to be achievements from a non-economic point of view as well as breaking sales records. Please no-one mention that Sam's still there, because I guarantee you he'll be happy to have Zelnick's hand up his ass all day telling him to put more staff on crowbarring a shitty MTX-stuffed online mode into every game. They'll be nothing but Take-Two's lapdogs from now on if you ask me.
It's sad on another level too because as I understood it, Dan was the one pushing to get Bully II off the ground for years and years as his pet project, only for it to get cancelled multiple times.