What you can add in advance ballistics is a MG3 (fast RoF high accuracy but terrible ammo consumption); Eventually you can design a Wiesel 1A1 with a Rh202 (Wiesel 1Mk20) or a BMD1 to replace the Ferret.
for Assault rifles there is a lot of ideas. AK-74, FAMAS, HK-G3A3 (20round magazine-> idea), SteyrAUG, FN FAL
SMG can replace shotguns: AKS-74, MP5, G3K, MAT49
LMG: L7, M240, MG3, FN Minimi, Ksp58, RPK, PKM, Stoner63
Precision rfile: Dragunov SVD, G3A3ZF, etc...
Rocket launchers: LRAC F1 (long range , powerfull, Heavy), SARPAC, M72, RR gun.
What can be an idea for the advanced ballistics would be to mix a bit the roles of the weapons. As an example, the Germans developed the Leichte MG3 for urban fighting. A lighter version of the MG3, a bit less powerfull but able to be fired from the hip without making the bearer flying backward. These kind of "light" LMG could replace shotguns, the SMG could fill a place between shotguns and Assault rifles (or pistols),
Most evolved assault rifles are enough accurate to be comparable to a precision rifle at 700m.
I think a good idea would be to fulfill dual-roles with advanced ballistics.