I think Ditko worked farther ahead on Dr Strange than he did on Spider-man and that, perhaps, he was planning a conclusion to his epic in any case. Stan, by his own admission, had very little to do with the Strange feature and Ditko probably used this freedom to draw ahead. Ditko also kept things "close to the vest" when dealing with Marvel staff.

I think his departure from Spidey was far more abrupt and I maintain that Romita Sr's first issue shows signs of being partially drawn over Ditko layouts or roughs. The first six pages are SO Ditko. It's very apparent in the Romita Sr Visionaries where the printing is much clearer than other editions. NOTHING against, Johnny Sr. I'm sure he was under orders to ape Ditko as much as he could. But those first six pages are not his alone.

Again, it would be betraying a trust to say more, but Ditko kept his career plans very much to himself.

Alos, Ditko did indeed hate sound effects. In our one and only too-brief conversation he told me how he loathed unnecessary SFX and hated the "pop art" pages that Stan was working into his later Spider-man issues.

I really can't think of any comic book I would rather see then a Lee & Ditko collabaration on Spider-man. It would be even better if it was part of "The End" series of books ( like Peter Davids "Hulk the End").

Of course the "lost" Ditko Dr Strange issues are a very close second!

Yeah, I think Ditko knew he was going for a while before he actually did -- he was ramping up his work for other companies in the preceeding months.  By all accounts, he'd been frustrated for a while, and probably not just on an artistic level.  Evanier has posted that there was a business disagreement with Goodman involving non-comics art use, as well.  Roy Thomas and Steve Skeates both say that Stan having Carl Hubell redraw (re-costume, really) a figure in the Looter story was the precipitating incidend.

I'm second to few in my admiration for Mr. Ditko, but I figure those last months must have been a real pain for Stan and show great forebearance on his part.  Ditko wouldnt' speak to him and didn't inlcude margin notes, and (in the Looter story) wouldn't do even minor revisions.  That must have made writing the book "Marvel style" a real nightmare.