I would also argue that none of these guys are slow. We move out a player in Berglund who was relatively slow and replaced him with Bozak, who is certainly faster (both as a skater and in puck moving). Stastny for ROR is basically a wash. Sobotka for Perron is lateral. Thomas or whoever replaces Brodziak is an upgrade. Pushing Jaskin and Thorburn down the chart is a positive speed gain. And then we have Fabbri and potentially Kyrou. The net gain is significantly positive.
It's hard to compare rosters since the Blues were so heavily injured last year without the proper depth to fill back in the holes. If you compare O'Reilly to Stastny as the comparison, then I think it's advantage to O'Reilly. He's better defensively, on the dot, has better, skating, and a better shot. Stastny has better vision and passing, but their hockey IQ looks equal. Comparing Bozak to Berglund, Bozak has the better hockey IQ, skating, vision, and passing while being better on the dot, but Berglund has the shooting and defensive skills. That's advantage Bozak. Perron to Sobotka, this is a wash where I'd argue defensive acumen, and IQ are about the same. Perron has the advantage on shooting and skating, but Sobotka is a better passer and vision. Perron does take some stupid penalties where as Sobotka is more disciplined. It's a wash but Perron fits our team better than Sobotka. Thomas replacing Thompson, the only thing Thompson has is his shot, and even that is close. Thomas is better in every conceivable way.
I think our 4th line is really where you're going to see a difference in player comparison. They're going to suffer a bit defensively as Brodziak and Upshall are better than Barbashev and Soshnikov defensively. However, I think Barbashev and Soshnikov add some more offensive punch and speed. Our 4th line won't be as reliable defensively late in games, therefore probably not used as much, but they are going to push play, be a bit more tenacious, and can be coached up on the defensive end.
Schwartz Schenn ?
? O'Reilly Tarasenko
Steen Bozak ?
? Barbashev Soshnikov
Those are the pairs I think you'll see after training camp and you fill in the ? with Fabbri, Perron, Thomas, Jaskin, or Kyrou. I don't really see Kostin, Blais, Foley, Stevens, Thorburn, or Nolan pushing into that w/o an injury. Jaskin would be my pick on the 4th line with Barbashev and Soshnikov because he's a possession guy while Barbashev and Sosh are more shooters. I really believe that Thomas would benefit the most from being with Schenn and Schwartz, splitting face-offs and defensive responsibilities with Schenn, but he'll probably start with Bozak and Steen. Fabbri will be on O'Reilly's left with Perron up with Schenn and Schwartz.
That's a definite improvement in the speed/transition game over what was there last year. That team also seems more like the Mike Yeo style team that beat the Blues in the 2015 playoffs.