I honestly don't think this roster looks better with Shattenkirk, Fox and ADA all in the same lineup --- not by a longshot. I think Trouba, for some of the grief he seems to generate, is a big reason why ADA and Fox were in situations where they could succeed. Not all that dissimilar to how Pionk is in a situation where he is more likely to succeed in Winnipeg.
Beyond that, keeping Pionk and having one of the quartet of him, Fox, ADA and Shattenkirk move to the left side would not have result in equal success from any of those guys, and IMO, would only further cut into the success we experienced.
As for Hayes, I don't really see a long-term solution. While I think we'd be stronger down the middle in the short term, I think the overall result would've been less than what we collectively saw this year. Especially if we're talking about keeping the defensive corps from above. That's an overall net loss.
And I think if we had a time machine to do it all over again, people would still be bitching about Shattenkirk, still bitching about Pionk, still bitching about Hayes, and most likely not even able to bitch about our short playoff series.