Heh well I thought it was a simple option. Maybe I was overthinking too much. I just wrote whichever the way I could think of right away.
The easiest fix for low range RC is to not have them. Make all R2,3 to R4. That would be a super fast answer.
If you want to make R2 and 3 useful, then I see the way I described top or other few other options.
1) Make R2 and R3 units more resilient against infantry. This will pretty much turn them into mixed infantry. Not sure this is what you want.
2) Change the linear damage reduction formula. So you do a lot more damage in R1 and R2 while less in R3, R4 and R5. The problem I see here is how much damage you lose from shooting units that are engaged. You lose a lot of hits from firing carefully at enemies that are engaged in your melee units. Increasing that damage will make all shorter range good in general but that also makes archers strong in general. Melee units will be used as cannon fodders again to buy as much time as possible.
I don't really see a simple option. Maybe someone else has a brilliant and elegant fix
