Don't get me wrong, I love WDW and we've been there many times, but the longest we've ever stayed is five nights. That's our limit. For me, the most important part of any vacation (after choosing a destination, of course ) is the hotel. I love nice hotels. It doesn't matter where I'm going, I will almost always choose a shorter stay in a nice hotel.
I made an exception to my own rule at the end of August. We stayed four nights at Pop Century (needed two rooms) and it took all my willpower to stay in that Value hotel. It turned out fine, but it wasn't my first choice. It saved us money (our second trip this year) and we had fun.
For me, it's always going to be shorter stay at nicer hotel.