Today I tried Ring of Fire mission with henchmen. Yes, I failed, but that is because I went for the bonus. I hear people saying it's too hard, it's impossible with henchmen, need a full party and god on our side. Why is Ring of Fire 'difficult' with henchmen? It's not. But if you die in the radius of an Ether Seal, it's impossible. Why? Because the henchies just stand there drooling, loosing energy and failing to attack the seal (out of range, apparantly...), or ressurecting you. It's annoying, and down right silly.
So, my suggestion: Make henchmen run out of the radius of the Ether Seals when they are low on energy (under 5), and regen. A bit like what they almost do with AoE spells. Or make it so that ALL henchmen have a Resurrection Signet, which is treated the same as yours (IE, it regens after killing a boss. And no, I don't think it does this anyhow as during that mission I was the only one to die after killing Cairne the Smug, and no res).
I think this would make playing with henchmen that little bit less frustrating
Henchmen and Ether Seals
Kaldor Meshekal
Curse You
All henchmen (Monk henches excluded) have Res Signet. They just aren't very smart with it. 
Lafayette
If henchmen run from ether seals with low energy then it may be hard to kill the seals with them then. They're inefficient with energy as it is and the hench warriors have low energy reserves. If they're fleeing with less than 5 energy then they're unable to attack and kill the seals. It's gonna create a cycle of going in to attack, having the henchies lose energy and flee, regening then them trying to attack before fleeing again. Etcetera.
Only the monk and ritualist henchmen don't have resurrection signets, and those of the others DO recharge after morale boosts. However, I agree they aren't particularly smart in using them. Many times they use them AFTER a battle instead of letting monks/ritualists (either people or hench) rez using reusable skills. Other times I find they just refuse to use them at all even when they're the only ones left - if they had used them, the rez countdown would start. But much of the time they use them pretty quickly after a death I find. But when they don't I doubt it's because of the ether seal - they are occasionally fickle in their use of rez sigs anywhere for me.
Only the monk and ritualist henchmen don't have resurrection signets, and those of the others DO recharge after morale boosts. However, I agree they aren't particularly smart in using them. Many times they use them AFTER a battle instead of letting monks/ritualists (either people or hench) rez using reusable skills. Other times I find they just refuse to use them at all even when they're the only ones left - if they had used them, the rez countdown would start. But much of the time they use them pretty quickly after a death I find. But when they don't I doubt it's because of the ether seal - they are occasionally fickle in their use of rez sigs anywhere for me.