I'm in the odd camp of believing the first season was the best. It was just so different. I didn't dislike the changes and was just happy to have something fresh on screen. I thought the klingons were great too.
I think season one did everything great except the plot which felt like they were trying to do 100 things at once. I was happy to see by time season 4 came around they calmed down and focused on one story much better.