Is this a step in the right direction for normalization? SQL 'inheritance' and Many-to-Many relationships
This looks like the party relationship model (see https://stackoverflow.com/questions/4969133/database-design-articles-blog-posts-photos-stories).

I recently went through something similar, combining different content types under a single table with subtables for each unique content type.

I'm not sure about the entity framework, but in the new model you have, you'll have an easier way to link content to other content by having a central place storing the ids/primary keys. It's a common design pattern, so I don't think there's anything "inherently stupid" about it.

I don't think you needed to worry about the first one, but the second one is obviously better thought out.