I think the thing that people have trouble with is the fact that Lucas created the PT story around including as many characters from the OT as possible - rather than creating a more logical story that only included relevant characters. I think it's funny that the characters are included as a sentimental thing for the old Star Wars fans, yet Lucas says the PT are for kids.
Don't get me wrong, I think the PT are fine the way they are. I enjoy watching them. It's just that I might do things differently if I were in the position to make them.