The X5 is far from outclassed, dynamically it's probably still the best off-roader on-road, if you exclude the Porsche Cayenne of course. The A6 Allroad is supposed to be very good on the road as well but i'm not a big fan. The Touareg looks too anonymous for my liking though the V10 Tdi offers heaps of torque, im not sure if its sold in the US though.
The FX 45, i'll be honest, i dont know a lot about, but it does look good. And as for Nissan never making an amazing AWD system? Uh... hello? Skyline?