At D3, it's just harder to find guards that meet aejones' rule of thumb (potential ATH + SPD >= 120 or they are not worth signing!) and have decent BH & P. In order to beat the press, you really want to have guards with 60s or better in both. You can make exceptions from that, but you really need to have a good justification to do so. When you skimp on BH & P, then your team will turn it over and lose to FCP teams. No question.
I find it difficult to take advantage of the advantages of zone at D3, but, IMO, zone is stronger than press by the time you get to D1. The reasons for that have more to do with early entries and the fact that the budget leverage advantage of taking a couple walkons is just massive at D1, compared with D3. My suspicion is that coaches learn that zone is bad at D3, but don't give it a second thought when they get to D1. So the simple fact that fewer coaches think to run it at D1, makes it look non-viable.