In the World Cup in 2017, the referee and video referee communicated with each other. I recall in the England vs Australia group match, a call was handed to Thaler (as video ref).
He started considering possible interference on a chaser and the referee told him he was happy with it and to move on. I would like to see a similar approach in Super League.
If a video referee can't tell, or its debatable, I don't see why he couldn't just say to the ref, what did you see, how confident are you? The ref could then say whether he had a good view, or was unsighted.
At the moment, we have a situation where a call can go up as a no try, say on the basis of an obstruction, yet be disallowed because of a questionable grounding, when the referee didn't ask for that to be checked on the assumption of a "no try" on field call and sufficient evidence therefore being needed that the grounding was fine.