because you're not just sealing off a single port, you're disallowing the use of the entire size and type throughout the ship. this is hilariously crippling to most ships, as most of their PD or primary firepower comes from one type of slot.
meh, most of the time i dont even remember to raise shields. just stack the armor (sometimes dont even do that....) and yell come at me bro! if i'm not woefully out numbered or out tonned, and if i dont make a strategic mistake(IE: an assault order on the map where the enemy deathball is also moving towards, want to thin it out abit by waiting on the other side of the map.), i come out just fine. for removal of shields from tri-tachyon vessels, generally thats ok, as they can extend their laser weapons to well over that of everything short of a hypervelocity driver, and most of them can outrun everything short of a hound, and with aug engines, can outrun thunder fighters. so in all cases removal of shields can far outweigh the cost of it not being there.
i assume you mean hounds. and with that i say meh, they are very, -very- good at escaping retaliation fire and dont really need shields to begin with, atleast i wouldnt choose shields over aug engines.