An aggregator composed of other news aggregators. As a concept it is great, but it will never come close to platforms like reddit. It's like newspapers, most of them just buy the news from agencies then complain about the decline of the (traditional) industry. An aggregator without curation will be so redundant and boring...
Instead look at those places that have something special and make you come back. They all have some differentiating factor. The WSJ from time to time produces high quality non-redundant content. The comments or content produced by users on HN and reddit are sometimes better than the news elsewhere.
Curation and the user base confer a site personality. This is why places like HN or reddit are so popular. Reddit offers a very high degree of segmentation to users through subreddit subscriptions. This allows users with perhaps very different personalities to get along by only focusing on things they have in common. Not only that, it incentives users to create, share and enjoy content together.
Y combinator has a true commitment to provide a simple platform to a user niche they are interested in. In contrast to the laissez faire curation approach of reddit, the strategy of HN is not as broad but for this specific niche is of higher quality. Although sometimes HN is used for Y combinator's purposes, they don't abuse it and many times the interests are aligned with most of their user base.