Have you been to downtown Fort Worth recently? You said it is not the best part of town, but in past years, some of the most valuable real estate is located there. The west side is where some of the richest people in Texas live. Not trying to be rude - but most Dallas people don't realize that there is a great city over here. I've lived both places and would choose Fort Worth over Dallas anyday. Much nicer.
Anyway - I have also heard great things about the All Saints daycare. There are also some great preschools downtown, such as First United Methodist, First Presbyterian and the Montessori school, which I think is also a daycare. Check them out - I think you will be surprised.