We have 4 kids too. Last year we stayed in a Fort Wilderness Cabin; they were 17, 16, 13, and 11 at the time, so somewhat close to the ages of your kids.
I picked the cabin over a family suite at All Star Music because
1)Quiet, I figured the separate cabins would offer more peace and privacy
2) More of a real kitchen for making breakfast in the mornings, or even simple dinners some nights. We were there for marathon weekend, so being able to make a real breakfast in the mornings and a "carbo load" dinner of pasta the night before was a real asset
3) Pool has a hot tub, which I prefer for every Disney trip--but was especially important for post race
4) On site activities/entertainment; ability to see the fireworks and water pageant from the beach, nice boat ride to Magic Kingdom, etc.
For us, the one bathroom thing wasn't an issue, but part of that is because some of us were running races REALLY early in the mornings, while others were still sleeping. It might be more difficult if everyone is waking up/trying to get ready at the same time.