Blackhawks will have deHaan back, which bolsters their defense. Plus their coaching staff will have had a few months to analyze the Oilers PP. Hopefully Tippett and staff learn the lesson from the Capitals decade of playoffs futility and develop plans B, C, D, and E for PP set-ups. It wasn't until Oshie and Kuznetsov joined the unit to take pressure off go to plays A (Ovechkin one-timer) and B (Green/Carlson shot) that Washington found consistent playoff success with their top-rated regular season PP.
I think the wildcard is what version of Crawford will show up. The playoffs hero of successful seasons past or the guy that tanked (or almost tanked) a few playoffs series and required the Blackhawks to bring in a good back-up? This year they traded away that option in Lehner so all the pressure remains on Crawford.
I think the Oilers PP is so good because they don't rely on set plays and can make scoring plays from every place on the ice. They have three terrific players (McDavid, Draisaitl, Hopkins) that can all make all world shots and passes, the hockey sense to get open, the feet to create time and space, and use different primary skills to attack. McDavid's also an auto zone entry. Chiasson and Neal are a couple of strong net front players, who only have to do that ONE job, and have different ways of acheiving that. Klefbom does a great job keeping it simple and has all the skills needed from a PP QB even if they aren't elite. I think Yamamoto, Bear, Green, Nurse, and perhaps even Benson are also viable alternatives who could come in if injuries strike and without rocking the boat too much.
The Hawks are certainly capable of upsetting the Oilers and any PP can get cold but I think the Oilers have more top end skill and better depth. The goaltending for me is more of a question on the Oilers side, it could either be a massive advantage or their undoing. The Oilers may be lacking a top 6 winger, a 3C, and a true #1 D but they also have a surplus of top end talent with 3 elite players up front and reasonable fill in's. Obviously Nuge and Yamamoto have them covered it's just whether two of Kassian, Ennis, Athanasiou, Nygard, or even Benson can step up. If you aren't going to have a sure thing it sure is nice to have options which Tippett has. The Center position is actually a strength due to the top end talent available (McDavid-Draisaitl, Nuge if needed) and a strong checking specialist (Sheahan). And just like with the wingers depth has at least provided them with the advantage of multiple options (Haas, Kharia, Athanasiou, Granlund?). Unfortunately Cave would've been a solid option as well (RIP). I also believe the PK has a deep list of options with the only real weakness being a lack of strong faceoff options outside Sheahan and Draisaitl.