I loved the show but I was content with how it ended. The Will Graham and Hannibal relationship was, in my opinion, explored satisfactorily within the series and I'm not too sure I would want to see it examined any further; they got more out of it than I was expecting they'd be able to get from their relationship, but I would be very worried that any further seasons would result it on treading too-familiar ground and for that particular relationship, three seasons was more than enough.
I could very well be mistaken, as I was when the show was announced and I expected it to be useless and merely cashing in on the name, and I'd certainly check out any additional seasons in the hope that there is plenty more to examine in an interesting way (particularly since the ending did bring it to a somewhat new dynamic, for a brief moment), but if it was to return my instinct is that they'd really need to let Will Graham go and take it in a refreshing direction (which they obviously couldn't really do for a straight adaptation of Silence of the Lambs given how the series ended).
I don't think that was Fuller. I think his idea was to have a black actress who had been raised in the deep South and let that play into the whole, 'wanting a new skin' aspect of Buffalo Bill.
At least I think so. Might be getting mixed up.
That would be a very interesting and relevant way to take the story.