I feel like it would have been okay to use him immediately without the "author of all your pain" nonsense. Hell, even that might have been tolerable without appropriating the joke brothers twist from Goldmember as the big dramatic reveal.

Quantum is a direct sequel to the Vesper story from Casino Royale. Skyfall more or less ignores that whole thing and is standalone (other than M). Spectre is where they became obsessed with continuity.