Does the original poster want views on the the best Russian bomber aircraft of all time, as indicated by the OP question?
Or does he actually want the pick of all WW2 'light bombers'?
As C.V. correctly points out, certain categories overlap, such as large capable western fighter-bombers,
which could tote a greater ordnance load than the dedicated Russian Sturmovik 'light' bomber.
Soviet fighters were smaller ( with lower powered engines) & unable to match the bigger Western types.
Machines such as the DH Mosquito would also overlap the light/medium bomber role, & also be
more mission capable than the best of the equivalent Soviet machines ( the Tu-2, IMO )..