Well, war is war. The Empire may be evils as a whole entity but that does not mean that each of its combatants is – most of them are fighting for their future or to protect their loved ones, just as many Alliance warriors are in just for the money and the fame gained slaughtering conscript peasants.
So, dark or not, better in the Alliance than in the Empire – which has its fair share of conjurers without any need of help 😀
Also in a setting with high magic the wizards are basically the core of the war – it is in facts a war of wizards where commoners are simply miniatures on a table and numbers. Weapons are mass produced thanks to magic, aerial troops can exist only by magic, fast and accurate siege weapons use magic, explosive ballista javelins are magical, potions, communications and espionage are magical in nature…