You can choose to ignore it, but depth at the wide receiver position is a huge concern. After Metcalf and Pittman, the cupboard is essentially bare. They have Roman Wilson starting in the slot, a guy who has shown next to nothing for two years. The two-deep consists of Ben Skowronek, AT Perry (whoever that it), and fullback Max Hurleman actually listed on ESPN as the back-up slot receiver. C'mon, man. They have NOBODY. Now sure, they can wait and add a WR in the second round, but something has to be done, and Concepcion is the perfect fit for what the Steelers need. So no, it would not be "preposterous" to draft him.
As far as not having a left guard, apparently they're happy with Spencer Anderson. Whether Jones reclaims the left tackle position or not is indeed a question mark, so I'm also good with taking Kaydn Proctor in the first round if he's available.