The P239 has its adherents too -- although it is heavy and a bit of a brick in shape, and has a low magazine capacity for its size. Despite those drawbacks, P239s just shoot well and some people love them. Unfortunately, it is now out of production and parts may be hard to find. The P225 is a great pistol too, and for now has the benefit of still being in production.
The 3913 and 3914 are wonderful, though, because they are a bit smaller and very svelte. (Ditto for the 3953's, the DAO version, which was made in small numbers by S&W until fairly recently, for specific Law Enforcement customers, e.g., New York City). These guns are roughly in the same size category as the Glock 43's and Shields -- but have the advantage of a little weight in their metal frames that makes them easier to shoot. They supposedly became too expensive to manufacture in the polymer era, although I always wonder if modern CNC machining wouldn't bring the cost of such all-metal guns down low enough to make it worth it to S&W to reopen the line. For the older S&Ws, parts may be hard to find, but there are enough of them out there, and enough old-school S&W gunsmiths and armorers still around, that you probably could find most of the parts you need by searching the internet and gun forums. But the old 3913/3914s themselves are expensive and becoming harder to find.
There is just something about a slim pistol -- a single stack -- that makes it easier to carry concealed. I currently have a XD-E, which is just pug-ugly -- but it works great and has the DA/SA features, and a decocker, which I want.
Bottom line of my meandering post is that I would love to see a single stack RAMI, with a width of 1 inch or even a tad less. It would rival the 3913/3914 Smiths in terms of size, handling, and shootability. With states gradually moving to the 10 round magazine limit (Virginia is expected to pass such a law in January 2020) the single-stack 9mm pistol with a >10 round magazine has increased relevance and marketability.