The .45ACP doesn't produce tons of recoil but enough for the muzzle to start climbing (ever fire a Thompson). I think it's a great concept, look at how low the muzzle is in relation to the grip and stock. For tight in work if you can dump a whole lot of .45 in a small area it would be great. It has limited potential as all around gun but that's not it's purpose. 10mm Would be my preference too.
Anytime you can replace skill with technology is good. This is why we aren't using swords anymore.
With SKILL most common cartridges to include .308win and 30-06 can be handled with minimal muzzle rise. Full auto takes skill and lots of it. Sub-guns are not heavy on the skill side. They were purpose built to be easy to shoot and handy. Which they are.
As armedsask pointed out, sub-guns are dead. The superior performance of intermediate cartridges far outweigh any benefit a sub-gun has to offer.
The evolution from sword, to bow, to firearm is not indicative of replacing skill with technology. It represents a logical and tactical evolution in how we fight and how the battlefield has influenced how we fight.
The use of optics on firearms is both a replacement of skill with tech. and an evolutionary step in combat. A rifle with optics provides the shooter a much easier method for which to score hits. The skill required to use iron sights can often match the success of an optic based system. However, the ability to identify ones target and engage at greater ranges with greater precision is the benefit of using optics. In todays battlefield such advantages are required to remain "competitive" if you will. The skill required to operate an optic with great success at extended ranges would be similar to the skill required to score hits at intermediate ranges with iron sights.
The Kriss system is not adapting to the requirements of combat, they're simply trying to "dumb down" ones ability to negotiate the ever constant action we call recoil. Taming recoil(especially in a pistol cartridge) is something that has been mastered long ago. The skill of the shooter will always shine brighter than the glow of technology...
Oh yeah, I have fired a Thompson amongst other sub-guns. There is no recoil with the Thompson and next to none with the Sten, Sterling, Uzi, SAF, MP5, or AR15 9mm guns.
TDC