Everyone in the books is important enough without being starborn--even Harry (though his effect on events may or may not be a direct result of his starborn nature).
If you wanted to sell me on the idea that being around and fighting alongside Harry has made them greater than they were (without specifically becoming starborn in some fashion, miniature or otherwise), then I'd agree. It's the same as with Tavi in the Codex Alera; he inspired his Legions by surviving things he shouldn't have, by using what he had to devastating effect, and by preserving the lives of those around him as best he could. As a result, the First Aleran became better, pound for pound, than any of the other legions we see (training and combat experience obviously playing a role here).
Dresden doesn't have a legion; he has friends. He inspires them, and leads them to be more than they were. He shares wisdom, knowledge, and experience with them. As a result, many of the events play out in such a way that their impact is far greater on the grand scale than they would be without Harry.
Also, don't forget that Fae fealty rules might apply; by bringing his friends with him, they become his tools, like the Alphas in Summer Knight. As such, when one of them changes events in such a way that indicates starborn-ness, it's more an extension of Harry than anyone else individually. Murphy killing Maeve is only possible because the starborn brings her there, for example; ditto for Molly's ascension.
Also, unless and until we see literally anyone other than Harry command power over Outsiders (without the use of a ritual designed to summon them)—the one trait we know for a fact that starborn have—as far as I'm concerned, Harry is the only one in canon.
WOJ implies Elaine is one, but I'll believe it when I see it. As far as I can tell, she's not been much of a fulcrum for any events, except for betraying Aurora at a critical moment.