Thanks for all of the fluff info on this matter. And with that, for me, logic would dictate a wizard did it. Lol.
Fun fact, when you grow up with your parents always listening to BBC Radio 4 you learn all sorts of interesting and varied words with no idea if they're in the common vernacular or not!
I imagine for the same reason the US army never used Kalashnikovs. They have their own stuff and it works for their purposes
I'll admit it seems like it might be a questionable assumption to say the two armour's are directly related. But just because they operated on Paradiso doesn't necessarily mean the Mowang have been using their super heavy armour the whole time. It seems to me like its equally likely they slapped the Mowang into whatever armour they had tried them out decided they needed heavier gear and started outsourcing R&D to a few companies. One potentially made the Mowang Armour, One what would become Daiyokai and potentially 1 the Yan Huo. Though I'll admit I'm curious now and will be peaking back through the newest book to see more.
Mostly "reasons". But I think partly because unique unit types are a function of their personality. Domaru are high cc Heavy because of the domaru unit being strictly bushi warriors. Unit "culture" isn't something you just replace. Top tip though, id suggest not taking what people talk about on the uprising fluff at face value. It's quite vague in a lot of areas and subjective (as in the source of the fluff is intentionally an in world source, who might be biased). Some people have got upset and turned to the hyperbolic to vent as well, stating a particular interpretation as fact.
No, that says that the troops wearing the Mowang suits are veterans of Paradiso, who have been pulled together into a single unit to use as the main shock line. That doesn't mean that the S5 suits were being worn before YJ captured the remains of the Kikuchiyo Project (said capture is explicit in Uprising). (Sadly, the Human Sphere unit wiki does not have Mowang fluff yet, or I would have quoted it here)