A lot of fans, especially ones that straight-up loathed the prequels are in "Fool me once..." mode. Memories of the Episode I trailer causing this massive hype unlike anything else are coming back. Go on a Star Wars fansite, or the comments section of a large website discussing the trailer, you'll probably find people tearing it to pieces, and lots of arguments.
Me, well, I don't hate the prequels. I think they could have been better, yeah, and there's definitely some script issues. But I liked Episode I when it came out (I was 9), and my parents did too, (even my dad who hates sci-fi/fantasy movies), and I didn't even know that so many people hated Episode I until I got an internet connection.
Still, I think it's best to go into the next film not too hyped yet not too skeptical. I'm just gonna throw everything I expect out the window on the day the film comes out. Until then, I'll just enjoy the ride.