Hi all-
We plan to add a zooming function to OmniOutliner. Currently planned for v4.0. It's definitely been one of the most popular requests. Please keep in mind if you would like to submit a official feature request to send it to
omnioutliner@omnigroup.com or from the Send Feedback option under the Help menu. This will allow us to keep track of the number of requests we receive which helps us determine it's priority.
Thanks!