Lately the regeneration & resurrecting spell has been brought up alot in the balancing area and most would agree that the Earthblood & Invocation of Nehek has caused huge imbalance in the online QB. I too agree with the idea that these spells need some adjustment before next patch. And I have some idea how. But first let me explain the reason why these spells need to change.
The main problem with Earthblood (also applies to Invocation of Nehek) is that it affects too many units. It is ok if they were like in TT where Earthblood grants regen only to mage's unit, and the Invocation of Nehek doesn't work on the unit that categorize as Large, Ethereal or Vampirics. But currently they are much more powerful than their TT counterpart. It's really beneficial for elite unit such as heavy cav and characters to have regeneration. However, since there isn't a limitation of the unit we can bring, such regeneration spell that affects large area could get magnified by casting on a full cav army, and more. Which would certainly put huge a disadvantage among those faction which don't have lore of life caster. Also too good for a entry level spell.
And as I was saying, the Invocation of Nehek shouldn't work on Large, Ethereal, and Vampirics. It is a resurrecting spell, not a more powerful version of Earthblood. I know some people would think that it will be too harsh of a change for the vampire player, since the statsline of the monstrous in their army are not outstanding. They need more survivability. But the thing is you already get raise dead spell to summon some meat shield to help negate damage. Then you need a spell to heal all of them? com'on. VC is supposed to use powerful augment spell from the lore of vampire to buff their unit help them in the fight, not spamming raise dead then heal til end to solve all the problems.
Earthblood - Reduce cast range, and effect radius.
Invocation of Nehek - No longer affects Large, Ethereal, and Vampiric units.
I would expect a lot different opinion since the Invocation of Nehek change I suggested is huge. So if you have ideas plz leave comment letting me know.