With 2 children in daycare, I have to say, it is unusual even at 18 months to have a room full of crying kids, so see if you can observe the room when it is not drop off.
I really don't have much worthwhile to add that hasn't already been said, but fwiw I wanted to second what notnafnaf mentioned - all three of my children when through daycare and preschool (multiple schools, many different teachers) and not one of them had a room full of crying children all day, even when the babies were really really tiny. I would try to drop in at mid-morning and see what the environment is like then - or perhaps just stay for a few hours in the morning after drop-off. If there really are children crying all the time, that to me is an indication that the place really isn't a good place for *any* child, regardless of IQ.
FWIW, I was also a hands-off the academics at that age too - didn't worry about it, and just followed my kids' leads... and chose preschools that had a similar philosophy (in our area, Montessori worked well - not just because it was Montessori, but because it was truly child-led in terms of learning and because of the wonderful teachers).
Best wishes,
polarbear
