Also as others have mentioned before, I think that the "curse" of the Druid/Fury is that his most powerful signature spells are available as scrolls and can in certain cases be more valuable to other classes than to the source class.
Insect Swarm, Plague of Insect and Embrace the Earth Talon can be good for anyone but especially with builds with inherently high accuracy buffs or ways to debuff FORT to land the spell effectively.
Avenging Storm is very strong for martial classes, of course especially broken with Monk SC builds.
Greater Maelstrom is a boon to all but seems like it was made specifically for the Arcane Knight:
Can get very high Arcana (in the 30s) and with some of the items Boeroer mentioned, reach very high PL on Avenging Storm.
Pulsing AoE spells fit well with a static, buffing/tanky approach. Stand your grown, buff, create hazard AoE, let the enemy close in and die.
Will work very well in combination with Combusting Wounds, Chill Fog, Freezing Pillar, etc.
Really enhances the offensive potential of a build that can be a bit soft on that side in late game encounters if focusing a lot on defensive abilities (i.e. instead of having to spam Blood Sacrifice)
Greater Maelstrom benefits from the Eternal Devotion fire lash.
Like many players, I try to limit my usage of scrolls to specific situations but the availability of these Druid scrolls has always felt a bit unfair to the uniqueness of the Druid IMHO, just as hypothetical scrolls of Whispers of the Wind, potions of Assassinate or Gloves of Disintegration would hurt the uniqueness of Monk, Assassin and Cipher .