I don't think 14.5 failed in the defensive compartment, if anything flak is almost required for any tanky non railgun ship, it greatly reduces strain on your shields and armour. I think it's only good that flak can't completely deny missiles, or completely counter lasers, the general idea is that these defenses are supportive to the other more conventional ones.
The only area where flak or pd failed are fast moving nukes, but they are all kinds of broken atm anyway so it's not the problem with flak/pd per se.
Now, I am not against more different ways to protect your ship, however I definitely disagree with the notion of this topic.