I am not even saying Willis is the man- but those holes that you mention mean very little if you have a hole at the QB spot.
Two points:
1. There is no clear franchise QB in this draft. As many have discussed over the past two months, one of the QB's might be really good. It could be Desmond Ridder, it might be Malik Willis, it could be Derek Strong, maybe it's Kenny Pickett. But none of those guys is a top-tier prospect worth using the #20 pick.
2. The Steelers have an NFL-caliber starting QB in Trubisky. Good arm, mobile, threat to run, moves around the pocket well, two playoff games already under his belt, or two more than Rudolph, Haskins and every QB prospect combined. He won a division title and a wildcard spot with mediocre Bears team, featuring guys like Taylor Gabriel, Trey Burton, Anthony Miller and Darnell Mooney as the #2 receiver and Jordan Howard as the #1 RB.