I like this, personally. The WWE has done a great job in offering both Big Show and Cody Rhodes great opportunities here. Big Show can either put Cody over or take the belt off of him and allow Cody to move on to a potential main event feud. I can't think of too many other people that could challenge Cody for the belt anyway... And no, Goldust doesn't count as a challenger for the title. As much as I think it would be a great match, it really wouldn't do anything to stir up interest. Goldust isn't exactly relevant in the world of today's WWE. I don't think WWE needs to go and have a "brother vs brother" feud just for the sake of having one.
I've really been enjoying the build-up of the Big Show/Cody Rhodes feud. They've really made it seem like Cody is getting under Show's skin with the videos and Big Show is poised for his revenge. On the other side, this makes Cody seem all the more "fearless" of Show, all the more ready to take on an opponent of Big Show's caliber. Could a feud with Goldust have accomplished that? The match would probably be better, but Goldust isn't exactly a picture of physical perfection right now. Big Show will be able to put on a consistent match and that really counts for something.
Whatever the result of this match, I'll be fine with it. Cody has had a great run with the Intercontinental Championship, having one of the longest tenured reigns in recent history. To add Big Show to his list of defeated opponents would be great. If not, it's not the end of the world. Cody is very much ready to move on past the midcard, so why not drop the title to Big Show? Show can turn around, put in some nice work with the title, then elevate someone else to his level and drop the title to them. Fine choice by the WWE here.