Unfortunately, the Avalon's rear seat does not fold (a fatal design flaw), where the Five Hundred has folding rear and front passenger seats. You could also mention the optional CVT, AWD, and DVD entertainment Avalon does not offer.
You must also purchase the top-line Limited to get the extra features (and the cruise is still optional), with a $35,000 price tag that is in a different class than the $29,000 Montego Premier. The closest Avalon is a $33,000 XLS model.
The price differential, especially when compounded by higher sales taxes, licensing fees, and loan interest needs to be taken seriously.
On the actual test, I think the Fusion's interior needed to go through the anti-screw up process. The rear seat is too high, killing headroom. I also agree that it is rather poorly styled. However, the new Camry's interior is putrid.