I’m not saying one line is going to dominate all through the playoffs, but as long as the rest of the lines can chip in I think our best bet is to keep the top line together. Boston, a team that plays a fairly similar style to us, loads up their top line with Marchand - Bergeron - Pastrnak in the playoffs with a lot of success. Plus we get very good secondary scoring from our defensemen. The graph is not the end all be all especially since some of them are a very small sample size and there are certainly line combos that will work with the remaining guys.
Since winning the Cup; Boston has missed the PO's twice(both times since the '12 Lockout), lost in the 1st round twice, lost in the 2nd round twice and lost in the SCF's to Chicago.
And they weren't even remotely a 1 line team for most of that time(Krejci, Lucic, Seguin and Horton were all productive players for them at one point).
Looking at recent Cup winners; I can't find a single one that actually "loaded up their top line".
Washington had Tom Wilson playing on the top line so Oshie could provide a threat on the 2nd unit.
Pittsburgh has deliberately keep Crosby, Malkin and Kessel separate as much as they can to spread out the scoring.
Chicago kept Kane and Toews on separate line to spread out the scoring on all of their Cup teams.
LA has Kopitar and Carter on separate lines.
As said; Boston had a very balanced top 6 when they won the Cup.
You might have an argument for Detroit given that Datsyuk and Zetterberg played together often; though I think having Lidstrom, Rafalski, Kronwall and Chelios on defense might have played a bigger role.
You might have an argument for Anaheim given that Selanne, McDonald and Kunitz played together; though Penner-Getzlaf-Perry is hardly a "weak" 2nd line.
Carolina had Staal and Brind'Amour on separate lines with Williams, Stillman, Cole and Whitney rotating on both lines.
Sorry, but I just don't see any evidence that loading up the top line is the correct way to go. Recent history says the exact opposite. You have to have a productive 2nd line, even if that means splitting up what might be an otherwise great line to make it happen.