It's more logical than saying "This is my opinion, ergo it must be it".
Especially when it comes to Nintendo, which multiple people are more than happy to repeatedly bash for being too "stuck in the past", so there's no reason to see why they would drastically change suddenly on this point, especially when yet again, the past clearly shows otherwise.
The extra difficulty mode along with the Trial of the Sword? Yeah, that fits along with past Zelda games of being stuff that's in the game normally (Although I will point out again, I think this extra difficulty does go a bit above the past ones, but not by much from what we've seen so far, unless they give bosses whole new phases or something).
DLC Pack 2 though, with the extra story about the Champions? Hasn't been anything like that in the past, so I don't see why it would be considered "dropped", or "Perfectly fitting in".