Scala, whose modularisation was strongly influenced by ML, already offers most of what 1ML is trying to do.
Scala is complex, and SML is pretty simple. (I haven't studied 1ML beyond the elevator pitch, which claims it's "minimal and uniform".) A very complex language with a large installed base can't offer simplicity.
Granted, I haven't used Scala since, err, 1.7 days? I think. I liked it, and did a lot of work in it in fact, but more as an alternative to Java.
If I didn't have to worry about compatibility with Java or the proven nature of the JVM, or satisfy sysadmins and management with the orthodox Java-ness of my runtime, I'm not sure I'd pick Scala.