I am aware of those spells,and did not mention them because the interaction is quite bad. As some one already mentioned, the trait only make sense on melee unit, where they are usually expected to die first.
revenants blessing ,most fight end under 30-40 seconds. This spell would be much better only if it increase the revenant life even by a tiny bit, 3-5s so you can move them around.
ethereal storm : it's hard to keep revenant alive, so this spell is useless in regard of the cost. The only revenant you usually have is the T4 lost evocation.