This displays your lack of understanding of the circumstances, or coding.
The resources you are referring to are moot fillers compared to what was reconstructed, from the ground up. Even the mechanics of the Primal Fights, which you try to use an example, had to be reconstructed from scratch, even though the land and modeling textures, did not.
Even the mathematical equations for determining damage has been fundamentally reworked, the fact that many aspects of specific fights (which are a striking minority of the game's content) are similar are actually an increase in workload, not a decrease. It is the quintessential difference between replication, and duplication, you falsely assume the latter - much to the discredit of your argument.
Using pre-established model presets saved them time in the graphical department, which is fortunate considering the depth of reconstruction other, larger projects, such as the map, likely costed them in development time.
The fact that this game continues off of a pre-existing lore is irrelevant compared to the amount of work done in the time-frame taken. The fact that you attempt to discredit this fact based off of comparatively trivial shortcuts taken in comparison to the new content created and the pre-existing content that had to be faithfully recreated displays your lack of understanding of the circumstances you complain under.
This is a new game. No less of a new game than one Castlevania to another, reused graphical assets or not.