@njb1 I haven't heard any more than what you have posted... state testing 2011...
I have not heard if there is any competition in the trials, like from the ADS bullpup rifle that is designed to operate as a replacement for the AKS-74M, and the APS underwater rifle by using special 5.45mm underwater ammo and standard 5.45mm rounds. The ADS was in tests last year for the Naval Infantry and the VDV as a potential new standard rifle.
Note that in the past the Naval infantry have had the specialised APS rifle that uses ammunition that looks like someone got a standard 5.45mm round and took out the standard projectile and replaced it with a knitting needle about 20cm long. The shape of the round makes it very effective under water and able to be used in a smoothbore rifle capable of full auto or single shot with a 26 round magazine. They have even developed tracer ammo for the weapon... which would be very interesting to see a video of. The problem is that while the weapon is far superior to any spear gun while under water, above water it is probably less accurate than your average pistol, so a standard assault rifle has to be carried as well.
The new ADS is a new bullpup design base on the A90 assault rifle. It has a tube that blows empty shell cases forward so unlike some bullpups you can fire it left or right handed without any adjustments and without empty shell cases hitting you.
The new thing about the rifle is new 5.45mm ammo that looks normal from the outside and fits into standard magazines but contains a reduced powder charge and the projectile is the length of the case with its base nearly touching the primer. This long length makes it efficient in the water and its performance is just as good as the APS underwater regarding range, accuracy, and lethality, while above water using standard 5.45mm ammo its accuracy is as good as the AKS-74M standard rifle, if not better.
With that sort of competition Kalashnikov will need to have something to give his rifle an edge in trials. I think a balanced recoil mechanism will increase complication in production, but not so much as to make it super expensive, and the effect on performance in burst and full auto fire seems very impressive based on what I have seen of the AEK videos on youtube. In full auto bursts the hits tend to cluster like a shotgun blast rather than string upwards like a burst from a rifle. There is a reason why shotguns are used for moving targets...