Honestly no I am not against it because the media on castlevania has tendency that when mercury steam said its going to have more exploration elements such as in Mirror of Fate or Lord of Shadow 2 people are saying its going to be 3D symphony of night which it isn't and I think that is why Cox and co have to clarify it. I doubt there will be backtracking but I do think there will be optional exploration which I am fine about . I love the story to be straightforward and for the exploration to be its own separate thing.
But thats the thing, just because it has exploration akin to SOTN does NOT make it a 3.D SOTN by any means.
There are many other things SOTN of the night had that LOS obviously is not such as leveling up, equipable weapons,armors,cloaks etc just to name a few.
So even if it had borrowed exploration aspects from the metrodvania that would not have essentially made it a 3.D metroidvania since there are other things in a metroidvania that makes it such.
I'm willing to be that most of the people who said it would be a 3.D SOTN if it had that kind of exploration where the same who disliked or even grew tired of it and simply don't want to see any metroidvania aspects in this game.