there are a few live vids of JD on Youtube. Old Grey Whistle Test and some stuff in Germany?
They certainly played a bit faster and more frenetically live.
From what I understand the Joy Division guys were more upset by the synths and funny effects on their songs.
I've done some sound engineering myself and it's a common complaint of bands that are not used to hearing someone else add to their version of a song.
I did sound for a punk band with saxophone once. I put reverb, just a bit, on the sax. I'd be an asshole if I didn't. It killed!
They totally whined like petulant 5 year olds after the show. But everyone not in the band loved it!
I think Hannett added a lot to Joy Division. He certainly did not do a hack job by doing the 'standard' things that everyone else was doing back then. New Order certainly wasn't running away from any of those Hannettisms.