I personally think that Sauron wanted him killed, so he sent ol' Goth to Gondor on the front lines. He's too ugly even for Mordor.
(Who knows...maybe the denizens of the Black Land had something called "What do you assign to Gondor?" and Gothy was at the top of everyone's list, after their orken parents of course.
![Stick Out Tongue](http://forum.barrowdowns.com/ubb/tongue.gif)
)