...what

Reading through it, his suggestion seems rooted on the idea that Metroidvania carries implications in terms of setting, perspective or combat, which is a complete fabrication of his mind not grounded in reality. It's 2024, the people that would know and care about the Metroidvania tag know very well what that tag implies; your "revelation" that Arkham Asylum is also a Metroidvania has been commonplace in discussions for a decade.

This addresses a confusion and an issue that don't exist, and the tag is so standard at this point that changing it would not catch on and would create way more problems than it would fix.