Hit is ranked lower then other stats primarily because a missed hit for feral druids effects us much less then any other class. Only 30-40% of our damage comes from white attacks, which is the lowest of the melee classes. So a extra 1% hit is only +0.4% increase in dps from white damage, as opposed to 0.7% for many duel weilders. Second, the penalty of missing on a special attack is lower for ferals because we use energy. A missed attack only consumes a fraction of the energy cost of the attack, where mana or rage users lose 100% of the cost of the attack. Finally we don't suffer from the loss of a global cooldown from a miss, with using energy and having a 1s global cooldown, we have more GCDs then we can ever use.
That is not to say you shouldn't forget about getting hit. Missed white attacks don't proc OOC and enough missed specials will consume energy that could have been used to land another attack. I try to socket hit/xxx gems in order to boost my hit up, but being short of the hit cap doesn't mean I'm a gimped dps.
As for the graph, the reason it doesn't make sense to you is because your assuming that the line goes through the origin (0 crit, 0 AP). That is not true in this case. the equation for the line in the graph is approximately y=100x+9000 which means that at 0 crit, AP is 9000. Another way of looking at it is to say even if you had 0% crit, you would need to have at least 9000ap before you started thinking about stacking agi instead of str. The primary reason for this is that a big chunk of our damage comes from bleeds which does not scale from crit at all, however all of our attacks scale on ap which makes it much more valueble.
Edited, Jan 27th 2009 8:42am by SirJac