Ideas and suggestions.

Remove all control spells from the magic books and make them not tied to elements (all at expert level), using separate buildings for each spell; this will reduce the randomness of artifacts in the Dragon Utopia and spells in the guild; and everyone has the opportunity to build a spell or something else (there, portal costs one thing, flight another, Dimension Door a third); the cheapest is flight, for example, 5k gold, wood and ore at 20 each, etc