What's the point? Their specialties are just ordinary... at least for most of them. Not counting Jelu and Dragon)
And the specialties of Jelu and Dragon (I don't know about Dragon, but definitely Jelu) are straight-up cheating... especially when you can buy them at the start. 9 snipers + the ability to upgrade elves/Archers into snipers. Now that is a truly unbalanced specialty... There should be fewer of those)) That's just my personal opinion..
At the very least, it should be done so that they hire a standard army in the tavern. For example, Jelu has 3 forest elves, 6 dwarves, 12 centaurs. (Just as an example).