Getting back to the subject of John Logan himself (rather than regurgitating decade-old arguments about the plot and characters), I don't think the success of Skyfall
means Logan has proven himself. As jeyl mentioned
a couple pages ago, Skyfall
was just as full of plot holes and characters acting stupidly as Nemesis.
The only thing Logan has proven in the decade since Nemesis
is his uncanny ability to bounce from one high-profile project to the next, glomming onto that film's success even though that success was in spite of, not due to, his screenwriting prowess.