I think, apart with LOS ATGM, the capability of vehicle to combine it with BLOS fire is an important point in the current arm-building. The most close to Russian '120 mm Vena' is the American concept of the Mounted Combat System - it's ongoing development starting from 2003. It used to have a 120mm main gun with LOS/BLOS capability, a .50 machine gun, and a Mk-19 40mm. Hovewer I should offer 30 mm axial autocannon like on BMP-3 in addition... Thus it will look as 'improved BMP-3'
I shoud put here a citation about MCS purpose and conception:
"It is a virtual certainty that future conflicts in the 2025-era will find US forces opposing traditional massed heavy armor. There will be occasions where the MCS will encounter such enemy forces and direct fire engagements will be unavoidable. Under such circumstances, Overmatching Direct Fire Lethality (ODFL) will be essential to FCS survivability. For a vehicle as light as 20 tons, however, ODFL as protection reflects a last-ditch defensive measure of desperation to be called upon only after the vehicle has gotten itself into a situation that should have been avoided in the first place. If the MCS is used in a manner that optimizes its capabilities and minimizes its operational weaknesses, the overall contribution of its ODFL capabilities to survivability will be relatively small."
http://www.globalsecurity.org/military/systems/ground/fcs-blos.htm
- I cant agree with it more...