This won't necessarily result in an overall better player base, really.

What I mean by this is; Those who want to get better will get better regardless of the level of content they do. Comparatively, those who don't want to get better, will not get better, and the people in the category of the latter will just burden the former. This is why I am against an increase in the difficulty of normal content.

What I could get behind, however, is an extra difficulty level to help better prepare people for the more difficult content, and then use this extra difficulty level as a requisite to enter the more difficult content, e.g., savage or extreme, rather than the only requisite simply being to finish the story.