GameBanshee has the first part of an interview with D.W. Bradley on Dungeon Lords MMXII. On the re-worked spell system:
More information.What new spells have you added to the game, and what changes are you making to the magic system as a whole?
D.W. Bradley: The most significant change was to make all magic spells share a common Mana pool, providing players much greater freedom of choice for casting magic spells during combat. Mana is directly influenced by the Hero's Intellect attribute, allowing players to decide whether to improve attributes for better Magic or Melee capabilities when they Level Up. Nether spells are no longer mixed with Nether Katals, instead, each Nether spell requires one specific associated Nether Katal to cast in addition to its Mana cost, but the Katals are consumed much more slowly, allowing Nether spells to be cast more than once with a single Katal (Alchemy skill makes Katals last longer). Rune spells were also revised to use Mana, and Runestones have been removed from the game. Casting times and cooldowns are now displayed for the spells when cast, and this visual feedback makes use of magic much easier and intuitive during battles.
The decision to assign the different schools of Magic according to the Basic Classes necessitated that all of the Magic Spells be revisited and rebalanced, and new spells were added to supplement the Basic Class associated with that Magic school, for example the new Rune Blast spell for Fighters, Bloodstrike (a healing strike) for Rogues, Frost Missile for Mages, and Shadowstrike for Adepts. A number of the original spells were also revised, for example Rune Speed now increases fighting and movement speed, granting Fighters and Adepts ability to run faster in the game for a limited time. The Warding spells moved from Rune Magic to Crystal Magic, however, the Boon spells affecting a multiplayer group remain as Rune spells, allowing Fighters to pump up and inspire the party for improved Melee combat.
The changes to the Magic system and spells represented a major undertaking for DL MMXXII, but I felt they were necessary to provide greater distinction between the different Classes, and I wanted the player's choice of Classes to result in very different gameplay experiences with regard to combat tactics and survival strategies.