Talkin about D's sense of humour I find it really refreshing and often very funny to read his quicks wits and banter here and there. In The Gambler "jawohl" scene with the Baroness comes to mind. Also I found Alexis's little comments about killing the Frenchman and such were very humerious. It is something D is not well known for but it very good at.
Talkin bout The Idiot and characters I am not far in yet but already I can understand some of the similarities you mention. Natashya is a very complex individual.
I am just now at the part where Myshkin is having lunch with Madame Myshkin and her 3 daughters. Even this early there is so many strands to pick up but Im keeping notes so i dont get lost.
