in x86 there are:
1. fully optional subset 3DNow,
2. version hierarchied subset SSE (if present subset with higher version, subset with lower version will present too),
3. mutualy exclusive subsets AMD-V vs VT-X.
Is such subset classes present in ARM 32s?
It is hard to imagine that CPU32_V1 is optional - there`re instruction basis.
CPU32_26BIT - loooks like obsolete? or it can be present in more than 1 ARM version? or it exists before ARMv1?
CPU32_V4T - specific only to ARM4 and disapear in later versions? like sahf & lahf disapeared in x64?
interest such relativities in all subsets described in fasmarm. (I want to try to port them to fasmg in alternate encoding style where processor and coprocessor directives from fasmarm could be in curse brackets before instruction or after word use) for that I need hierarchy of subsets.

There are many many different makers of ARM chips. All those manufacturers have included different subsets of the instructions. If you want to combine some sets together then you can, of course, but if there is someone out there still using some esoteric version of the ARM core then they might find it annoying to have to manually avoid some particular instruction that has been included by selecting something else.

I think it harms no one to keep everything separate. It improves flexibility. It improves compatibility. It makes the programmers job easier to have the assembler detect any invalid usage of instructions.