Ahhh, the Firbolg sniper... if memory serves, in D2 they had a base precision of 15.
Nice. They also avoid the Bane's cold aura that may be a problem for some armies... and an archer normally shouldn't be sent alone.
I'd favor either Botulf or Vision's Foe (preferred) over the Ethereal Crossbow, 'tho, as both ignore target's MR. And AN+eye loss is
so evil.
If you're looking at assassins, Spirit Helm + Phoenix Rod is a nasty, expensive, 1-2 punch. Add a Rime Hauberk if you want to cover yet a third element.
Of course, if you're going REALLY profligate, the prize for funny (from the winner's POV) + profligate + unreliable might have to go with empowering an assassin until he can cast Gifts from Heaven.