Delta has come up with the Diamond Seal ceramic for kitchen and lav, due to low lead requirements. I have not seen any indication they plan to change the design of the very successful and reliable 1300 series ( R10000 rough valve).
I did not know about the 1300 series. I do like a ceramic disk, but it sounds like the 1300 series must have proven reliability since it has been around for some time.
The basic internal operation of the 1300 cartridge, both the old style and the new one, uses the time-proven seat and spring mechanism. Reliable, plus easy and inexpensive to repair.
The seat/spring design is so good, it has been copied by almost everyone at one point or another. Price Pfister is now using it in some of their Pfirst models.
The ceramic seat is interchangeable with the rubber seat/spring combination, but the mating surface also has to be ceramic, which is probably why they have not converted the tub/shower valves.