I agree. Yet the question is how much is that worth. One thing to keep in mind is that even the "bad" defensive CFs are usually pretty good fielders. Trout might not even be the best defensive CF on his own team. Peter Bourjos is no slouch.
We see this at work on the Reds. Drew Stubbs is a talented CF, but he's just sort of average for his position because guys like Carlos Gomez and Michael Bourn also play CF. Excellence in CF is pretty common and it's a bit premature to declare Trout superior to his group of highly qualified peers.
So definitely give Trout points for defense, but I recommend a little reserve in turning it into a gazillion dollar prize. He has a solid defensive advantage. If everything else is equal, then that should put him over the top. I think some analysis on this has been quick to get to everything else is equal.