Imo, if you're losing to defenders, I think something else is wrong.
I don't see why. The defender is a solid ship that can do a lot of work if built and flown well. It's not the most cost efficient ship, but it's by no means garbage. It just usually takes more work to get value than other ships of similar or lessor cost, so it's not often a great choice for tournaments.
It´s not just that it takes more work, its that it is predictable and expensive.