Sacrifice - how to use properly?

[bukimi]

I know that I cannot resurrect 5 level units.
(I did last time I played with time back and paladin's resurrection)
But they are very useful for blocking the enemy.
And having lvl 4 units is useful as they are tough and can be resurrected as well.
Shouldn't sacrifice give more health than it takes?
They way it works now makes no sense - it is expensive to cast and gives almost nothing and I do not have a turn or unit to sacrifice...

I had inquisitors but they die very easily.
Archmagi do not deal any real damage so only their shielding ability may be useful.
I cannot find demonologists this time I play
Yet I have a lot of paladins to refill.
Never tried gorguanas - they seem a good idea