I have friends who are also lamenting the closure of Bug's Land. Their son recently turned five, and as passholders they have many fond memories with him there. Yet, redundancy of the rides aside, I feel like one of the bigger gains of closing Bug's Land is that the park is eschewing an AP hangout. Indeed, small children visit the park as tourists, but with respect to my friends, the area seemed to me an enabler for passholders with small children to remain at the park with the little ones long into the evening. This family talked about strategizing, sending one adult for drinks, and then another to go on a ride, using the land as a base camp.
Perhaps I'm unqualified to evaluate this, not being a parent, but hearing their stories made me wonder how young is too young to go to a Disney park. In their experience it sounded like they were getting more out of the visits than their son. It's also worth noting that the Grizzly Challenge Trail offers much to occupy young children. I like
@Curious Constance 's quote because I think it sums up the whole situation well. After all, rides akin to those in Bug's Land can be easily found in other amusement venues and Disney rides ought to aspire to a better standard. Bug's Land offers conventional entertainment, which is what these frequenting families have turned their Disney park experience into.