I'm in the middle of Imajica right now, and it's making me realise how disappointed I was with Scarlet Gospels. It's an O.K book, but compared to some of these earlier works, it just doesn't stand up.
I've read the theory a few times now, that he may have, for health reasons, passed the book on to someone else to write and that's how it does feel. The differences between Imajica, Weaveworld, Hellbound Heart, Thief of Always - and many of his other books - compared to Scarlet Gospels feels significant enough.
And of course reading the concern of you all in here over his inactivity - though maybe we can hope he's just hard at work on a new book! - makes me wonder if he did get to a point where he wanted done with the book and passed it on to someone else.
It felt, at times, like a Clive Barker novel but there were shifts during the book that didn't always match up. You'd get an extremely well written chapter that caught your interest, and then it felt off.

Maybe I'm going mad, though. It's just, Imajica is so good as is Weaveworld that I find it hard to conceive the same writer wrote those two books, and many others I absolutely adore, and went on to write Scarlet Gospels which - again - is O.K, but is just not near to the same imagination as the previous works.