Shepherd’s aspect is the only worthwhile way to use druid companions (outside of poison creeper) at the moment. Wolves can perform slight tanking and provide a slight amount of fortitude while Ravens can add vulnerable, but none at a rate high enough to make them worthwhile on the toolbar (again, aside from shepherd’s aspect) once you get over level 20.
The main issue is that companion damage is bugged - items/aspects/skills/paragon which boost the tooltip don’t actually increase the damage. If you guys can help us get the word out to Blizzard, that would be great.
Here are a couple of subforums we have going discussing the core issues: