They did but, even though it is equal to US O-7 in NATO standards, they consider it more of a senior grade of captain. They only wear one row of gold on the cap visor, and have a forked and tapered flag rather than a proper rectangular admiral's flag. But their army brigadiers are not "generals" either, so they are used to their in-between status.
But what choices are there? Commodore is out because it doesn't shorten to admiral. They whiffed with commodore admiral. The Germans have "flotilla admiral," but the meaning behind it (small torpedo vessel so numerous that they were grouped into flotillas of squadrons) would be lost on people today. In practice (at least 25 years ago) the USN didn't really make a distinction between one and two stars except on formal paperwork and of course uniforms and flags; they were all basically rear admirals, some more senior just like any other rank.
Yeah, wouldn't it be good if you could have an office with some YN who could do a lot of the PN stuff and vice versa? Also won't this help out in rates which are have lower advancement opportunities? Back in the day for instance AC and AG were notorious for getting smart sailors quickly to second and first class, then they took forever to make chief. But if they could be competing in a "pool" of airdale rates, seems like it might be more fair. Or maybe that's not a problem anymore.
Tradition is great and like I said this seems like a culture shock to me personally, but sometimes you have to shake things up and if it's better for sailors, well, so be it.
Though I will say my niece is an ATAN just coming up for third class, and she is NOT happy about this.
Yeah, there are only so many letters. When they revamped all the WW2 ratings in 1948, Aviation Machinist's Mate was AMM, but they had to cut everything down to two basic letters. AM had already been Aviation Metalsmith for many years, so Aviation Structural Mechanic inherited that, and AMM became AD, though why the D I have no idea. So eventually you ended up with AX and AZ, which I would still have to look up to remember what they were.