The question is, does it really offer improved control or hit probability over the PDWs from FN and HK, and advanced SMG designs like HK's UMP. It does look sufficiently compact to offer some advantage in concealability for security personnel.
Rifle caliber carbines are the tactical du jour at the moment though, I wonder how much attention this will actually get.
I wasn't able to run down the actual weight of a Blackhawk long barrel in same caliber but sounds like the Kriss is a decent trade off.
The trick downward motion of the bolt might approximate the reduced weight (to same result) and, since there is a fore grip on the piece, one handing it should not be an issue. (Stability for one reason, economy of motion / facilitating even a quick aim, for others)
I'd rather see a reduction in rate of fire - that would improve on a lot of potential complaints as well as logistical and tight tactical situations.