It's an interesting and good point, but in my idea of the team next year, I still have Kampf as the #4 C there as well.
I know it's not a popular decision, but he excels at taking DZS and PK, and I don't see a specialist in that area emerging or in the market who can.
However, it would hypothetically help both Matthews and Danault in that regard, especially with Matthews taking too many DZS, because with Marner gone, I think we will have to optimize Matthews' offence as much as possible.
But for me, Danault is there for 5v5 security in the playoffs with Nylander, and given that, at least in the version in my head, there's a 37-year-old Marchand on the other side, having a really defensively conscious C for them would be best IMHO.