Intellect is usefull for a Paladin (I am using the ring that gives +5 an takes 20% gold after battle) - to boost spells like Armor of God, Healing, Resurrection, and most importantly, Phoenix. I found even the Adult Phoenix is incredibly usefull in tough battles.
Yeah, for single stack Adrenaline will be sufficient, but why would you do that? It's boring. If you play undead, go all the way!
You'll learn to appreciate how cool some of their units are. Ancient Vampires and Bone dragons rule, Cursed Ghosts are excellent tanks... Skeleton Archers are not as powerfull as in the Legend (due to nerfed Dragon Arrows) but can still pack a punch in huge numbers. And I think Pirate Ghosts have possibilities too. But the best are the Necromancers, a truly versatile unit that raises fodder, incapacitates spellcasters, casts Plague on the whole battlefield (and yes, it works on Black Dragons too), and is very fast to boot - meaning it will most likely act before the enemy does. The only problem is that its attack hits your own troops too, but that's the undead way - you can resurrect them by life drain or Evlins.