First, you have to understand that all of the Disney properties are pretty outdated when it comes to their attractions. They're clean, well-kept, well-organized, but the rides are pretty much the same as they were 40 years ago.
Second, you have to be strategic when going to Orlando. Going during peak times is the first mistake. But even then it can be bearable if you a)show up an hour before opening, b)eat meals off hours, and c)plan your day meticulously, strategically timing attractions during their least busy times and using the FastPass feature to its best advantage. We went multiple times when our kids were little, and never had any problems with lines. It was always a relaxing and enjoyable experience.
Also, we made sure we didn't wear the kids out. We only went to theme parks every other day, with off days spent playing in the pool. And on days we went to the theme park we ended our day by 3 or 4pm. I think the last time we went our kids were 9 and 12; and we stayed until just after dinner.
But we always watch with pity at the families who are having an absolutely miserable time. The parks are not worth it if you're not able to avoid the crowds.