Ornamental pear trees definitely have problems:
http://guilford.ces.ncsu.edu/2013/10/bradford-pear-a-mixed-blessing-in-the-landscape/
I wouldn't replace it with a crepe myrtle, though. Most crepe myrtles get big, although there are new cultivars that are smaller:
http://www.clemson.edu/extension/horticulture/landscape_ornamentals/crapemyrtle/varieties/
However, for a small tree, I would recommend ornamental crabapple, dogwood, or redbud.