Another aspect of the 'wrongness' of the return was the children appeared not to have aged at all despite his long absence.
My original thoughts on seeing the girl that the grandfather introduce was
"Oh, hello, this is the the daughter"
However this didn't seem to pan out.
As I said I came late to the party. Your comments about the newness of my idea does seem to have been explored though because, after reading your post above, I discovered this :-
Dissecting 'Inception': Six Interpretations and Five Plot Holes - The Moviefone Blog
Which seems to highlight some of the misgivings I mentioned in my first post.
I have no doubt there will be a sequel. Too much was left untidy at the end IMO.
I wouldn't be surprised if the wife makes a reappearance in the next level up.
By this I mean this plot line gives all sorts of opportunities. It could easily end with a new born baby or some old guy who has just died.
Incidentally, and I may have mentioned this before, I'm becoming more convinced that this form of dream is the underlying argument for life after death.
As I mentioned above, in recent years, I have experienced this form of 'reality' in my own dreamscapes. That is I have begun having dreams where I live a completely different life. Waking and sleeping for forty or fifty years with all the mundane events one experiences in 'real life' only to wake and find it all a dream. I suspect that in those last gasping moments of death where the brain is rapidly loosing it's grip on reality there is the possibility of vast time lines of dream existence; the only difference being that at the end you don't wake up.