We recently updated the Owl in the simulator to get a lot more damage out of it. We are still in the process of updating our default gear rankings for casters though. We're in the middle of rolling out our "version 3" gearing strategies, which is taking a little longer than desired... but we're getting there. Ideally we'll have it updated for default balance druid strategies this coming week.
In the meantime, you could create a custom gearing strategy to pick up the new ranking for it until we roll out our own updates.
Normally we would update much faster after making a change to a trinket like this. But we just happen to be in the middle of this huge improvement to our system, which is slowing things down a bit. Sorry about that... but we hope the inconvenience will be worth it for everyone when it's done!