The 2nd vs 4wd argument at baja was had many years ago when the trophy trucks came along. they showed that light weight, high hp, mondo travel, and big tires could overcome the 4wd advantage. took a few years to build in the reliability, but once the gap closed, 2wd trucks started taking the overall wins.
With Dakar, the dunes are the only real place where 4wd could trump a 2wd. the new hilux is a lot lighter than its 4wd predecessor, so it will be quite interesting to see how it does overall. it's like going from a big truck to a rail buggy.