I guess I am in a minority, but I think Pop Century will do alright. I agree that small children will greatly enjoy the large icons (my nephew would love that 'big wheel'!). I know from experience that the All-Stars can be the hardest hotels to book! On all my trips to WDW, I have never stayed there (and I tried twice to book it), since they were always completely booked or had minimum night stay requirements. So I think that a hotel with a price even less than the All-Stars will be quite popular since not everyone can afford deluxes or even moderates. Price is a huge factor to many, many people. I think Pop Century will definately find it's "nitch".
I was riding a bus in January to AK, and when we drove by Pop Century, everyone on the bus thought it looked cool and wanted to know what it was!!