Here's the thing, though... clearing most heroic content is decidely hardcore from the perspective of most of the raiding community. YOu can't sit on the fence. Either be hardcore and communicate that ('we're a heroic progression guild') or raid normals. If you want to say "we're a heroic progression guild, but we're going to limit raids to 3x a week" that's fine. It communicates that you aren't consumed by raiding, but that you still have high expectations.
TLDR: The issue isn't the hardcore part. It's the Semi- part.