We must not forget that the most important people at the Seder are the children. Since one of the two Torah commandments to be fulfilled is והגדת לבנך, "tell your children", this must be taken seriously. (The other Mitzva is to eat Matza.)
Because the children are so important, we must gear the Seder towards them. It is nice to be able to share deep concepts among the adults, but it must not be at the expense of the children.
Even if we have to speed up the Seder, it is preferred over creating boredom for the kids. This is the reason we implement several unusual activities during the evening. Aside from מה נשתנה, we dip the Karpas in salt water, we take drops of wine for the ten plagues, we sing fun songs like והיא שעמדה and דיינו, and we make a game out of hiding the Afikoman. All of this, is to keep the children involved.
And by the way, it is written in the שלחן ערוך that it's a Mitzva to be certain that children take a good nap on Erev Pesach. We must not forget the children.