Yes they will.

The reason Discos and Runners and outperform Stock Xterras is because they can lock their center differential, which makes a full time work like a part time. So that means a full time can only match a part time by trying to imitate a part time, part times are superior in offroad conditions.

But Discos and other SUVs designed with offroad in mind goes many steps further by adding electronic traction stuff to, again, imitate a part time system with lockers. The Defenders are also full time, as is the H1, and yes, they can all outperform an Xterra. But try taking a full time system with three open differentials and it'll perform no better than a two wheel drive offroad.

Give me an example of decent/proper/non-blindly-loved Jeep or whatever with a fully open fulltime drivetrain and NO ELECTRONIC ASSIST than can outperform a part time.