(Grand?) Admiral Zaarin was, as many of us know, an excellent strategist. He did, however, make a few errors, largely due to his own flaws. But, his biggest mistake..why did he not develop the TIE Defender in secret? Without Defenders, Vader and co would not have been able to have prevented his coup de'tat. He /probably/ had the Secret Order watching him, but he was a particularly tricky bugger..I'm sure he could have pulled it off.