A right click would suffice. It's not pre-nerf ASC strafing runs. Plenty of time to escape the barrage zone. Certainly more time than I ever had vs I&R/Recon Support Company 
That's a gamble. If you're even a second off with that, you're running a high risk of getting the MG decrewed. At the very least you're dropping models. At the very least, you have to pack up instantly. And that's all that matters when grens are now shooting it in the back.
Yeah the barrage itself is okay
Hell no, the barrage isn't just "okay", it literally hard counters an MG off the map. If that's just "okay" to you, then you're getting it waaay too late. It's strong because that MG is the only thing stopping you from mogging the allied players with your panzergrens. Once it's gone, you walk all over them.
This is 4v4, mind you. In 4v4, you can literally just tech T1, get nothing out of it (get squad size upgrade), tech T2, and bring out the 254. Then after you get a Marder and you've still got it out before the first greyhound.