Stan, initially I interpreted the question in the same way as you did, as asking whether the speaker or the amp is more sensitive to cable differences. On further reflection, though, I think he is asking about whether the speaker may be more sensitive to cable differences than to amp differences.
My answer to that is, yes, it is conceivable in some circumstances. If the amps being compared have negligibly low output impedance, such as most solid state amps, and if the amps being compared have no problems supplying the required power and dealing with the impedance characteristics of the speaker, and if the amps being compared are high quality and have no significant sonic aberrations, then changing cables could conceivably make more of a difference than changing amps.
Speaker sensitivity to cable differences will increase if speaker impedance is low, speaker impedance fluctuates widely over the frequency range, speaker impedance reaches low values at bass frequencies or upper treble frequencies, the phase angle of the speaker impedance is highly capacitive at low frequencies, or if woofer damping is especially critical with the particular speaker, or if cable length is long. Several of those things can also increase sensitivity to amplifier differences, though.