I like bluewater, there are lots of coffee shops, it's a triangle so hard to get lost, you can park easily for free, and it doesn't have the shiny floor issue that I found in Meadowhall hell (where the light shines back up up again so is coming at you from 2 directions and gives me a headache). But yes, it's heated, I guess people who are used to shopping outside do tend to turn up with coats, you will just be inside, so dress for it !
I do think some people arrive thinking any shopping centre will be hard work and get themselves all worked up. (I used to be like this).
It's just a place with shops together, there are maps around the place, coffee shops and easy to nagivate.
And yes, for children there are 2 (or is it 3 now?) playgrounds, a soft play, a cinema, mini golf, and lots of restaurants aimed at children, it's not just a place to go shopping.