Looking for reasons for why he's struggling isn't "making excuses for Brassard". Realizing that the team is desperately hurting for puck moving talent, which is a huge reason for why both Malkin's line and Brassard's line have struggled this year, isn't "making excuses for Brassard". If anything, the Brassard sucks group should be looking at this context more, instead of just looking at the numbers and screaming "Riley Sheahan would be better as the 3C!".
But it is making excuses when you find an excuse to wave away every single piece of evidence pointing to Brassard sucking and being the major architect of his downfall and that of everyone around him.
I've looked at the numbers. I've looked at them in just about every conceivable context. They all point to Brassard being probably the worst 3C in the league compared to his team. Which means, yeah, Riley Sheahan would be better as the 3C.
Rust-Cullen: 38 minutes together
Kessel-Cullen: 13 minutes together
Pearson-Cullen: 9 minutes
Those aren't sample sizes. Those are so small that you can basically throw them out. Compare them to the sample sizes for Brassard:
Rust-Brassard: 99 minutes
Kessel-Brassard: 169 minutes
Pearson-Brassard: 183 minutes
Comparing how Kessel and Pearson have done with Brassard vs with Cullen pointless because of how small of a sample size it is with Cullen. The only players that have both played at least 50 minutes with Brassard and Cullen are Hornqvist and ZAR, but you really can't compare those guys either because their usages were way different with those two guys.
So you complain about Sid and Geno because its Sid and Geno, but complain about Cullen because of sample size. How on earth are you meant to compare how the wingers do away from Brassard?
Personally, I'd say you use the flawed samples as best you can, and when they pretty much all point the exact same way... you accept what they're saying without a really good reason not to.
I posted the NST pages that showed those stats weren't true. Cullen-Letang was better at generating high danger chances, but Brassard-Letang was better at generating shots. I think I originally missed the "quality" part though, I was just looking at their overall shot generation.
Brassard-Letang has SF/60 of 32.35. Letang-Cullen has SF/60 of 39.95.
Or to do it with -Rel stats, as you've put in your links, it's Rel +.026 for Brassard/Letang and Rel +7.46% for Cullen/Letang.