Yes this discussion has been had before and I disagree. He's in charge, so it's his call, so even if it wasn't originally his idea, it's still a shrewd move to order it. Her word choice really doesn't specify who's idea it was.
Stanley has been offered plenty of great ideas before, and he has repeatedly done whatever it is that he wants to do. He's been counselled to appoint warlords based upon ability rather than looks, and he still promoted on looks. It's not impossible that the tri-link was offered to him as counsel,and it was fully expected that he would ignore the benefits of in it favor of his own idea. So Wanda's statement could have been taken as "We really didn't think he'd even consider the tri-link, let alone actually order it to be made."