its a good question, let me try to provide a good answer....
The A4 is interesting in that there's no other mono-poly like it out there.
put it in a room full of vintage polys and monos and it standz up rather well. btw, It stands up rather well against $4k euro rack. Why? because you reach the limits very quickly with vintage polys and others. Like say a Jupiter 8, or ob, you hit the sound designer wall pretty quickly.
I think its best not to worry about the traditional idea of poly on the a4 (though, personally i think that elektron should provide a para update, for faking 8 voices, but thats not going to happen).
Refocus on the alternative concept of poly sounds on the A4: on the fact that no synth i know of can lock 4 notes on one step another 4 notes on another step and then have many many other sound locks across 64 steps. One one track you can have/get a huge amount of synth mileage going on.
i.e 64 steps is like 4, 4 note, different sounds overlapping with some stunning reverb to boot. Then there's the p-locks.
As a mono, on 4 tracks its outrageous what you can do and where you can go.