Not that I agree with the statement that Sustr and Parayko are a wash, but I also find it funny that Parayko will definitely improve and Sustr will not.
Speaking about any player in absolutes when they aren't 10 years into their career is a little crazy. Scott Gomez was awesome once.
I don't think anybody is saying Sustr won't get better. He's a solid defenseman and still young enough to keep improving. But Parayko is younger, arguably better already, and considered by lots of hockey folks (not just Blues fans) to have #1D upside. Doesn't mean he'll get there, but given today's market you hold onto those guys for all but a massive return.