I believe the Pens would still win if they had Letang and they had Johansen, having that extra offense from the back end would have been huge and given the Preds even more issues trying to defend another star that can burn them. For the pens, yeah Johansen would have made Arvidsson or whomever else, more potent, but the Pens were still a rock solid team without Letang in that finals, adding him in would have put them even more over the top, while adding Ryjo for the Preds would have likely not embarrassed them as much, if anything.
It wasn't the Preds scoring that was the problem, it was Rinne not being as good as he needed to be at times and the Pens speed burning the Preds D.
In addition to what Jenkins pointed out, losing RyJo hampered their PP. They lost the option to work things from down low, and were forced to run everything from the points. Not the end of the world with their D... but it was one of the reasons they went 0-8 in the final 3 games - including 0-4 in game 6.
And well yeah, Nashville would have to defend things differently and it would be harder on them... I question how we'd play if Letang was in the lineup. Our game these playoffs were
F U G L Y for the vast majority of the games. But that was to an extent, by design. Sullivan took what he had and played everyone to their strenghts and turned us into a counter attack team. But this wasn't the same team as last year. From Christmas on last year (15/16) we were the best team in the league. We came into the POs hot, and we were for the most part destroying everyone - if not on the score board, at least in terms of on ice play - both in the POs and down the stretch. That never happened this year - even when we had Letang in Dec. Which means... even if we had had Letang... would we have played in such a way that would have shut down the other teams the way we did? I honestly do not know.
Here's the breakdown per month from last 16/17:
Oct: 4th in pts, 14th in SAT (50%)
Nov: 19th in pts, 4th in SAT (53.4%)
Dec: 2nd in pts, 14th in SAT (50%)
Jan: 23rd in pts, 16th in SAT (49.5%)
Feb: 7th in pts, 13th in SAT (50.5%)
Mar: 7th in pts, 11th in SAT (50.3%)
Apr: 11th in pts, 29th in SAT (41.7%) - 5 GP
Now compare that to the year before (15/16) from when Sullivan got hired:
Dec: 23rd in pts, 1st in SAT (58.3%)
Jan: 10th in pts, 6th in SAT (53.2%)
Feb: 8th in pts, 4th in SAT (54%)
Mar: 1st in pts, 1st in SAT (57.1%)
Apr: 4th in pts, 19th in SAT (47.7%) - 5 GP
I mean if you ignore April where only a handful of games were played, and both times we were resting players... there's a pretty significant difference going on - even when we had Letang. I mean in terms of SAT, our best month last year barely eclipses our worst full month the year prior (aka ignoring Apr). So while sure Letang would have changed things... our game was no where near where it was the prior year. Which means I question how much it would have changed things - at least in regards to who would have made a bigger impact on the ice between Letang and RyJo.
It still boggles my mind that we managed to win the cup.