The major strength of Rationalism is its universality. If I can think something is true, you can too! The lack of interest Rationalism has in sensory input is definitely a weakness. There are senses such as taste that cannot be proved by logic alone.
Rene Descartes had a theory about wax and rationalism, called The Wax Argument. Descartes suggests that when we see, touch, or smell wax in its solid form we all call it wax, however, when that wax is melted it has changed completely but we still call it wax, the logic of which has been thought through and not sensed, if we had just sensed the new properties of the wax we most likely would