My wishlist:
1 Floating barrel - will make a lot of difference in accuracy.
2 Full top cover rail - Provide real estate for a variety of accessories.
3 Adjustable stock - One size does not fit all.
4 Effective muzzle break - For recoil reduction and control in full auto .
5 Weight - Not exceeding 4 kg, less than 3.5 would be awesome.
6 Piston driven system - reliability.
7 Should not be too fat or too long- ergonomic to use.
8 Transparent or translucent magazine ,or at least one with windows - to keep track of the rounds left.
9 Ambidextrous - Ease of use.
10 Different barrel length variant - SBR,Standard,Marksman.
11 Prevent overheating - ways to prevent overheating under intense firing.
Rifles from which OFB should take inspiration:
AK 12
Scar H
Galil ace
AR 15
AEK 971
SLR 1A1
Insas 1C