Paul Giamatti isn't my favorite actor to begin with (or maybe it's just that I though Sideways was crazy overrated), so I may agree with this assessment that his casting as John Adams could be problematic. I've always been a fan of Adams and I have the book on which this mini series is based.
I haven't read it all, but I own it. Sorry, Mom (and Amber, as it is displayed on my bookshelf). Maybe I'll start it over again.