even if I agree on other matters

For me the 5975 chrono is not a usual 2 subdials chrono.
It is a measurement instrument for 3 types of data: Speed, heartbeats and distance seperating an event from the oberver.
Thus, the "chrono" doesn't need more than a 1 minute scale.
Adding 2 subdials to the 5975 would have needed to shrink the 3 scales and put them were there is room (which there wouldn't have been enough imho).
The movement could have been the one in the 5170 but it wouldn't have cost T€.52 but more than T€.70.
We can always prefer this nice movement to 28-520 but it is a choice with consequences (price). And as the 5975 has a solid case back you wouldn't be able to admire the manual chrono mvt.
Concerning the 2 pushers vs Monopusher, I would find the 2 pushers choice more balanced aesthetically speaking (even if I like the monopusher too).
The problem of the monopusher is that it is usually bigger and sometime is not nice when weighing on the right side. A matter of taste.
And personally I may prefer the 5975 dial layout (I love it so I know I'm biased on this matter) to the 5170 black which white markings are usually to strong, too contrasted (from what I saw on last years 5270P which annouced the 2015 5270s) and I also regret the loss of the pulsometric scale.
I'm not willing to impose my opinion but as I see many don't get it, I sometime find it is not fare (the case, lugs and bezel are one of the most beautiful since the 5070) and I just wanted to bring my PoV to the discussion

Cheers EDJA.
Mark