[Illuminated One]

Yeah, autoflanking is pretty annoying.

Some spells (destruction or even worse armor of achilles but Gifts from Heaven and Flame Erruption, too - all more or less "natural" choices against dwarves imo) are ridiculously hard to use because of their range/precision issues.
Your only option is to (attack)*x(spell)*y(cast) or something and it's bad enough to only cast one to three spells and risk your mages up close before the AI takes over. Now with autoflankers this becomes impossible at all since you don't know if you move forward or backward. It doesn't actually matter much if that's one or hundrets of miners summoned.