Why was Beethoven's 8th so unpopular?

I also love the Eighth. I'm not sure I've seen any modern-day critics panning this symphony (I don't think they'd dare). Many of Beethoven's works were criticised in his time - mostly because he was such a revolutionary and was writing music of the sort no-one had heard before. They thought he was a madman. Interestingly, Beethoven himself had a special affection for his 'little No 8'.