The other thing to remember is that some aircraft are more nav critical than others. As such they are often more appreciated and rewarding. On MC-130E's we had 2 navs and an EWO; they were a huge part of the mission success! The same can be said about almost all other C-130s. I am sure the F-15E WSOs are equally appreciated for getting "on target, on time". Former C-130 Nav friends that flew AWACS & JSTARS all reported a "lack of challenging a mission".