Alluminum is ALL about looks. I think Yamaha is just capitualating to the masses on this one. So many people believe that because the Honda looks better, it must be stronger, blah, blah. I wish Yamaha would have just developed a better steel frame.
There's really no reason for Alluminum. It will not handle crashes or impacts better than steel. Do not believe the hype. Alluminum cracks in situations where steel will dent or bend. Alluminum is not the key to light weight, just look at the KTM's. Allumium frames make the bike harder to work on because the frame is much chunkier.
Yes the frames are stiffer, but who needs that? I think Alluminum is more about benefitting the manufacturer than the consumer. Cheaper to manufacter, more sales.
I'd say, grab an 05 when the price drops because all the ingnorant masses see the Alluminum framed 06 in the magazines and HAVE to get one.
Aluminums just a fad, yamaha feels they have to keep up with the joneses (honda, suzuki)
Hopefully they figure out that theres some of us who perfer steel before they lose all our business to KTM.