I test drove a 5-speed 3.5 liter Altima back in '02, right before I bought my first WRX. The negatives for me were the feel of the front-wheel-drive and the waaaay soft suspension, but other than that it was a great car with a lot of torque. There are lots of V6-powered cars out there that will lay down the law to a stock WRX; you may as well just get over it.
At then end of the day, all of this is just magazine racing. If it's really all THAT important to you, find a friend with a 3.5 Altima, go to the strip with him, and settle it.