I am actually a big proponent of the way Salem approaches backside blocks. I have even taught this to both players and coaches so they can teach their players. That being said, some of the technique/elements you need to make this work well continue to get overlooked and kind of forgotten as the years go by. First off, it's much more effective (but also more demanding on the athleticism and steps of the OL) to do this with bigger splits and widen the backside defenders further from the play. I have always been in favor of this but Salem has preferred to go with tighter splits than what I think is ideal for awhile now. That makes it more difficult but still doable... you will just also need the timing of the exchange and FB/HB steps to be perfect and consistent. This was one of the big problems in the WF game, especially if you look at the counter plays. They used to teach a one-step counter by the HB but Friday night I saw backs taking three to four steps before changing directions and it made the timing for playside and backside blocking pretty much impossible. The pulling guard was already making contact on the DE kickout block before the RBs even had the ball. Again, that used to never happen as all the ball carriers were drilled on this non-stop, every single practice. There were even many times where a more talented back might not start over another back because he isn't consistent/good enough with his pre-exchange steps.
The other big issue up front is with the TE and FB blocking. It's pretty hard to understate how good Jaelyn Allen and Jayveon Jones were in this regard for the previous few years. That has had a very big drop-off so far this year, which is to be expected but needs to improve dramatically.