Essentially, what's up for discussion is how we deal with those gray areas because theme reviewers have been inconsistently applying the content vs. presentation guideline. These are things that are technically content but maybe not something the user will need beyond the theme. Custom post types, taxonomies, non-presentational metadata are all things that are not in a gray area. Those aren't up for discussion. Those are the clear-cut cases that we settled long ago. However, there are new scenarios that we haven't considered as a team.
Footer copyright text is a good example of something that's typically theme-specific. The theme users wouldn't care about that with the next theme.
Creating portfolio projects via theme options or custom widgets is probably better handled by a portfolio plugin that the theme integrates with. It's nothing more than a CPT disguised as a theme option. The theme user would probably not want to re-add all of their portfolio items when switching themes.
Then, there are some that we don't have an answer for. That's what we're discussing and trying to figure out. Ultimately, what we're attempting to do is clear up some confusion so that reviewers can be more consistent.