Raven is a very useful skill. As quickly becomes apparent by looking at the above table, the damage per attack at level 20 is 21-23, which is excellent. At that rate, it would take 628 hits to kill Diablo on Normal, which is excellent and much longer to kill just about anything in Nightmare and Hell. Without needing synergies, this skill is immensely useful even in Normal difficulty. The druid constantly has to keep track of his ravens and recast the skill as they "die", which is very simple to do. However raven is one of the best druid skills there is. Many smart players invest 10-15 points in Raven. Having a swarm of crows constantly pecking your enemies is extremely useful to the druid and his party. /snark