Keep in mind that volley fire costs 20 munitions, and is followed by a cool down. Also at med to long range it takes a very long time for it to suppress/pin. in my experience the best and easiest way to deal with Rear Echelon Troops is to use your own mg's to pin them. also when you realize you are facing someone using 2 or more Rear Echelon Troops and are using the volley fire ability often, they are sacrificing their ability to buy upgrades unless they are sitting on munitions points and building munitions cache's.
and remember when facing units that can pin, you must keep your units spread out. also remember Rear Echelon Troops can only volley fire on one unit at a time. if they switch to fire at another unit the ability turns off and the cool down starts.
I hope that helps.
I'd actually say that most of this post is inaccurate. No offense.
I've seen Volley Fire suppressing and pinning at medium range incredibly fast. Short range is basically a 2 second pin and rivals a Heavy Machine Gun. Squads will even be suppressed at long range.
Volley fire doesn't actually go away immediately if you switch targets. It is possible to suppress units after you've moved with Volley Fire.
I even had this situation go down:
1) Sturmpioneer comes up, I pop volley fire, pin him, he retreats.
2) I walk over to the cut-off point. Like five seconds later I see some volks coming at me. Volley fire was used like ~8 seconds ago.
3) Me firing on the volks suppresses them.
There's a lingering effect that allows you to suppress. My initial reaction to this new volley fire was "I guess I just need to run into the fog of war when I see it happen" but the suppression is so fast and it doesn't go away when you break line of sight!
I'd argue that Cover is a good counter. Cover and range used to mitigate this ability very well in the Alpha. That being said I've suppressed troops and that were in green cover without even needing to flank. Green cover can protect you but it's a gamble.
The only good counter right now to deal with Volley Fire is buildings pretty much. Buildings and vehciles.
I can't imagine that Rear Echelon spam is very good right now though. The cost of the ability is a little prohibitive.
Oh! And you can use Volley Fire while in a building. It's just something that you can do. I've stolen a building and then spammed Volley Fire out of it like ~5 times in a row and completely dominated one game.
The ability is out of control right now.