Just because you have never used the Teuton hero bonus, doesn't mean it is worthless and others don't use it.
Sorry, but I have to disagree. You are talking about "you can use the hero to acquire resources other tribes don't have access too." - in the beginning we are talking about ridiculous small amounts and later even less.
That you think a Gaul's hero bonus is useless shows me, that you never played competitively. There are so many instances in which a Gaul hero saved the day.. or the artifact to be more precise, thinking that the stupid plunder bonus is more valuable than the extra speed... argh. Not attacking you, just pointing out the lack of experience.
But at least we agree that none of the other bonuses even comes close to the Egyptian hero bonus. That's a start!