I never really understood why parents think a daycare setting can be custom fitted for their child. Honestly, a parent who has a child in a daycare setting with all age/maturity levels needs to realize there's has to be some flexibily on the parents part.
Yes, a parent should have certain requests met by the provider but it's a give and take. Otherwise the parent is going to be better off hiring a nanny that can provide the "custom fit".
During the summer I have to adjust my days when I get home. My son goes to daycare that has all ages, yes he's too old for naps but given there are children there that need the nap, his sitter has him lay down. He usually falls asleep. So I know that I need to get him wore out. We usually play football, basketball or some kind of activity, he also may stay up for an extra 30 mins at night. But really is that such a bad thing, I don't think so.
On on the flip side like you said, if your child is outgrowing the naps, there is that cranky period, but again your nights have to be adjusted to fit those child's needs. Making the shopping trips short, when you get home have more of a wind down period, maybe make bath time sooner.
I guess that really doesn't give you advice, but as a parent I have to agree with you. There is only so much "custom fitting" in a daycare setting with all ages.