Such short and rather terrible wording leaves a lot to be desired. In addition it's noteworthy that the article is most likely not well researched, as it states that only IBM has used RISC in an 'esoteric' workstation, while HP being still in research phase.
At the time of the article (June 1987), the PA-RISC-based HP3000 and HP9000 had already been in the market for more than a year (introduced Feb 1986). IBM's 1986 ROMP-based PC RT was not targeted at a mass market, but still a fine seller as an high end workstation (*1). Likewise the SPARC-based Sun 4/280 was introduced in early 1987 and became an instant seller. Last, but not least, 1987 saw several MIPS-based based work stations delivered (*2).
Long story short, the article seems rather intentionally geared toward ARM and tries hard to present it as special.
That aside, I would think it's for most part about the general RISC nature of the ARM, and the way in which several simple instructions can be chained to form complex ones. In particular, due the way of conditional execution without stalling.
A hint here is the comparison with the 80386 which has dedicated instructions for various register width or data item sizes. By being default 32 bit wide, ARM does skip many questions about 8, 16 or 32 bit handling. In addition larger items can be handled by chaining. Such as incrementing a 64 bit value by using two adds:
Similarly, all the variations of
MOV of a 386 dependent on instruction and mode can be synthesized by combinations of
LD*/MOV with optional shift factors.
Bottom line: It's a rather non-specific description pointing to RISC in general and ARM in particular.
*1 - And eventually used in 1988 for the first massive parallel RISC system with several hundred CPUs.
*2 - Given, all of them were designed for a high end market with top notch performance, while ARM targeted the low end of personal computing.