I will address your post backwords.Why? What's wrong with it ? It seems to have met the Army's technical requirements & has already seen induction with a few constabularies.
It's a good thing that forces are interested in adopting it, if it is because jvpc fits their bill, then great. I am not the operator, so as long as operator is happy my complaint is irrelevant.
What's Wrong with it, - There is nothing wrong with the gun, the issue is how I see the system. I might be completely wrong and it might be the most radical system fielded. But in my limited perspective, the gun is a lazy effort.
Why - It's the same Insas design, same recoil system, same bolt assembly, same recoil spring, and shitty single-stage trigger. The caliber is a 5.56x30mm proprietary ammunition. In concept the idea is similar to 5.7x28mm FN cartridge, but the bullet is not optimised and instead it turns out to behave like weak 5.56 nato squib load.
JVPC and the cancelled Minsas, both take a relatively hot round the 5.56x45 known for it's flat shooting and extreme muzzle speed, and cut down on it's energy to lose the only thing that was actually going for it.
The rifle still has the AK style long-stroke piston, when there is no necessity for it, a simple blowback is pretty much the norm for PDW's and SMG's. and finally, look at it, it still has a bayonet lug on the barrel, I don't think you will be able to cycle the thing suppresses.
These are some contemporary PDW's in the market.