Nothing in that review shows that the Note 3 "should have been tri band." Furthermore, that "reviewer" should not be dealing with Sprint devices, as he clearly has a prejudice against Sprint.
Maybe he lives in a market with overall poor Sprint coverage, thus should use a different wireless provider in the first place. Or maybe he lives in a market that is still in the early stages of LTE deployment, hence is not even close to full LTE site density. Without knowing his location, we cannot say for certain.
But I can practically guarantee that this "reviewer" is not an S4GRU sponsor, so he lacks knowledge of Network Vision progress in his market. My guess is that he does not care. Because of his negative bias toward Sprint, he expects the network to be automatically peachy once Network Vision has started and does not cut Sprint any slack to get Network Vision finished before he renders judgment.
AJ