While echidnas prefer termites (particularly larvae), I don't consider them termite specialists as they also feed on ants, earthworms, the larvae of beetles and moths and smallish beetles.
Did you see them on the last episode of Richard Fortey's series about 'living fossils'? He showed a skull which had a big bulging braincase and talked to a specialist who enthused about their abilities. I don't think of termite specialists as showing much intelligence (you couldn't fit much brain into a giant anteater's skull) but perhaps echidnas are different