If the narrator of your story needs to stay outside the action, then Omni is the right POV. Michener chose Omni in his epic novels for that very reason. He wanted Hawaii, Alaska, and Texas to each stand alone as the all-important protagonist. Choosing 3rd or 1st person for any one of these works would have created an intimacy between reader and narrator that would have lessened the impact and importance of Hawaii, Alaska, or Texas as the leading character.
In less formal stories, Omni creates a problem for many writers because they believe it gives them license to head-hop. Many writers have shown me text that states Omni is a god-like character telling the events of a story that only he or she knows.
Therefore, why can’t they head-hop?
There’s a difference between God telling you what John and Julie are thinking versus “John and Julie” telling you. The trick is to always remember Omni, a unique and distinct character, is telling the reader what Jack thought or did or felt. It’s not Jack showing them. That’s why Omni not only is able to tell you what Jack thinks of Steve driving drunk, but can also show you the police car waiting up the road, or the innocent bystander using the crosswalk ahead of them. Omni switches from one point of view character to the next in a smooth, gentle fashion that your reader will very quickly learn to trust.
While Omni is more formal and less intimate, on the grand scale of things, as in epics like Michener’s, Omni is your man. One suggestion though, when choosing Omni, make him a unique, formidable, and intriguing character. Give him a voice just as entertaining and endearing as any character. Or make him as non-descriptive as possible. And limit head hopping. Every time a writer jumps from one protagonist in a scene into the head of another, they risk disrupting the intimate (there’s that word again) relationship forming between reader and character.