That statement isn't entirely accurate – at level 20, Orah gains a significant advantage over heroes who don't have the Spellcasting skill: when casting a spell, her turn comes 40% earlier, which is quite substantial for an "average" Academy hero. Therefore, the ratio mentioned above would be 1.4/1 instead of 1.1/1, which is more than enough for effectively using one of the race's main strengths (magic) against an opponent who relies on the strength of their army (Orcs, Humans, Sylvan, Dwarves) or has chosen Education instead of Spellcasting, or opted for a fast-paced game while Orah develops her ability.