One has to ask themselves, when talking of new ideas: I get where the benefit would lie for people interested in a non-command career path, but what's in it for big Navy? Other than a marginal QOL/job satisfaction increase for a tiny percentage of its officer corps, how would something like this help the Navy accomplish its mission? I would also offer that there's already a path to something like this for guys who just want to fly - it's the SAU. I can see the Navy's answer to this kind of proposal: "Wanna stay in the cockpit, and stay out of the operational part of NAVAIR? Go reserves and join the SAU."
I wouldn't equate the SAUs with a "Flying Career Track." SAUs are manned (for the most part) by SELRES, which means they've elected to give up their benefits in the immediate future. A Flying Career Track would allow someone (be it Warrant or LT) to continue to serve actively and then get the immediate payoff at 20. Your comparison is kind of like saying, "You want to be a professional race car driver, but don't want to travel the country racing, so become a driving instructor at a school." They're not really the same thing.
Historically, you'd be right on if you replaced "SAU" with FTS/TAR, as it used to be the way you could fly continuously for 20. Now they've adjusted the system to mirror the REGNAV communities, so it's not "as" good a deal as it once was (but still a decent deal).
All that said, none of that answers your question (a good one, IMO): What's the Navy get out of this that it doesn't already have?