Rau's sweet spot has always been on the edge of the crease and as you pointed out he did very well on W with Bjugs. But Rau's numbers were basically the same at W as they have been at C, so I think that's a wash. The flip side is the 3rd line with Ambroz and C. Reilly needs a solid dig, setup, SOG and FO% workhorse guy @C like Boyd, so I can see a good argument there. The best C potential we've got are Rau, Kloos and Boyd. If Boyd is on 1st C with Rau on W, who would you put on 3rd C? Lettieri? Isackson? Lettieri has wheels, but I'd have questions about whether the real time line chemistry and his ability @ C w/ Ambroz and C. Reilly works. That may send them back to the marker board too often and yeah, weaken the 3rd. And Isackson...no. Then you gotta deal with the trickle down effect with Warning and Bristedt again.
Overall, I'm comfortable with the lines as they are now going forward. Let's see what happens. I think the 3rd line as it stands is poised for a 2nd half breakout. C. Reilly is finding his scoring niche, but needs more SOGs, I'm positive Ambroz is not happy with his 1st half performance and I expect him to step up...SOON and Boyd is a constant on that line...you know you're going to get a strong effort from him every night in all facets of his game.
I agree 5x5 has been a bit weak, and they've probably relied too much on their stellar PP this season for Gs. Gotta fix that... PK%? I'm not too worried about it. Over the past three seasons they've avg. 83%, and they're @ 82.5. If they shutdown the next 10 PPs, they're at 85% which is better than last season (84%). This team is not far off the mark from being dangerous.