I think Defense matters if it is a part of the game which you like, especially plunderers who are worried about retaliation. I had my defense over 600 and realized that even that much couldn't keep the best of the hood out. I took it all down, deleted Basil and Deal, took it down to the 100's replacing it with fp production and attack. As a result, I have been plundered 4 times this year, and produced thousands of FP's using the space I saved. On the other hand, I was able to immediately snipe the plunderers for a combined 200 FP or so in retaliation, which goes back to the point that everybody hates a plunderer, and none of the three were able to get some 1.9 friends.
I would rather use my shields for 30% attack to get a little farther in GBg.