Look at female solo leads in continuing series of all kinds. TV's Buffy had two heroes who held her heart: Angel and Spike, plus a few other, much more mortal, lovers. In books, today's "kick-ass" heroines always have more than one man in their lives, providing all kinds of romantic conflict and leaving the reader wondering, "Who's she going to end up with?"
Janet Evanovich's wildly sales-successful bounty hunter, Stephanie Plum, enjoys being pursued by hunks Morelli, Ranger, and Diesel. Sookie Stackhouse, Anita Blake, even Scarlett O'Hara (oops, not a series there) have multiple concurrent love interests. Even Rachel Caine's married Weather Warden, Joanne Baldwin, has two men pulling at her emotions.
Your average "kick-ass" heroine can be found as a matter of course in today's best-selling urban fantasy genre, which often run as series. Every one of these heroines will have at least two men panting after her, and they'll be alpha males to out-alpha any other male in the area. If the heroine is human you can bet money her lovers won't be. Humans are just too, well, ordinary to interest today's K-A heroine.
And Wondie is the kickin'-est-ass heroine of ‘em all!
Thus, it is my contention that Steve Trevor is no longer needed - or WANTED - as Wonder Woman's love interest. As such he would bring inertia to a series that needs to intrigue its readers.
These days Nemesis (portrayed in the book as a pallid, though WW-adoring, man-boy) has dumped Diana, and Achilles (greatest warrior of ancient Greece) has proved himself anything but an alpha male. WW should think about collecting a harem of male admirers, not only of the extreme alpha type but, for variety, include a few gammas, those guys who combine alpha and beta characteristics. Not only would this give "Wonder Woman" a modern feel, but it would add spark to the series and keep the readers guessing as to who might wind up with Diana, even if for only the immediate night.
I think Diana might enjoy it as well.