The screen size doesn't bug me at all (viewing distance and all), but what I can't stand is the variability in quality. Some shows and movies play just fine on my iPad, but there are other times that I cant get a decent stream to save my life, and I constantly have to re-start streaming to see anything other than huge blocks in place of what should be detail. No reason for the drop off in quality, no change in my bandwidth, no one else using it - just sometimes, i can't get a decent stream. And that is just about the most annoying thing in the world. Sometimes you don't even think about it, but the first time you watch a movie on your iPad (one of your own movies, from the video app), and you have constant high quality throughout, you have a little sigh of relief you didn't even know was waiting to come out.
That's my little rant for the night.
Oh, that, and how long it takes to get back to watching a movie if you get an email. I hate (hate!) sitting there wondering if it's worth stopping to check my email when I hear a new message come in, because i know it'll be a solid minute or more to get back to what I was watching.
But the screen size really doesn't bother me all that much.