Answer is quite simple.
It's Volley Fire and Kubel.
Voller was veru useful but was nerfed because it was too punishing to retreat unit so fast and let's rememeber that it costs 20, has a timer and RE are not mobile suppression platform.
On the other hand they gave us Kubel which is doign excatly same thing (but way better) which RE did before nerf
The Kübel is a dedicated suppression unit.
Relic nerfed volley fire because they won the engagement against any other unit they were facing, while being only a builder/supporter unit. Builder/Support units are not supposed to win engangments against combat squads on their own. You are comparing apples and pears. Otherwise you could also complain about maxims and HMG doing also their job, but you chose not, because crying about OKW is so fashionable nowadays.