Clearly the design intent with that Eitr cost is so that you can't soft-spec eitr and still use them. It's the ability people who go EE/H or EE/S get to use.

The skeletons are very strong, but they have some fundamental flaws you need to work around. You should also be giving them your barrier whenever possible. Considering they last effectively forever or until killed, I think the eitr cost is justified, especially when you consider we'll eventually have 4 of them out.

It's very clear the best combination will be 3 archers and 1 melee. The archers are extremely potent, and help offset one of the skeleton's biggest drawbacks, their slow melee speed and tendency to whiff attacks cause of knockback.