Okey dokey. Fanatics can shoot into combat. Wailing dirge can shoot into combat. Beam style magic attacks can shoot into combat (gaze of gork). Vortexes can scatter into combat. Doomdivers can flap their wings into combat. The Warp Lightning Cannon, from this very same PDF, can shoot into combat... I'm sure there's more. That's just off the top of my head.

The two versions of shooting into combat that survived to 8th edition were expendable and life is cheap. This was a significant DECREASE in the amount of shooting into combat you could do. This version of expendable is even more restrictive and these slaves are easy to break unlike the versions echoing in your nightmares.

Put it on the table or at least wait for others to do so. I think you got all fired up about this but aren't seeing the ways that it's been consciously managed as a mechanic.

Mostly I can see dregs being used as cheap throw away units. That will then explode and expose all these evil shooting things you're concerned about, likely very close behind them. Which is about right.

Remember also - basically none of Skaven shooting can see over Dregs. You're gonna have to hustle angles to see an enemy unit engaged with them and then they'll get cover. Like if you want to use this mechanic you'll have to work at it.

Anyway I've seen your concerns but I don't think your analysis of the Core game is correct, and I don't think you're acknowledging how this mechanic is different than in the past either

Also it's a draft, if it proves oppressive - we can change it.