I'm conflicted by this slightly. On one hand I see it as a great idea for great minds to come together, and on the other hand like it was mentioned, this seems to create a lot of additional "noise". Meaning more applications that require reviewing over others with solid ideas.

What are exactly the merits to determine "good" untested founders?

My other question is, which has been eating at me slightly is the trend of the startups I have seen come from Y Combinator being "extremely" similar to each other. Of course there is going to be overlap, but even the backgrounds of founders are largely similar creating this trend of "hive" mind ideologies for startups. Is this intentional?

Overall, I'm curious to see how it will turn out either way.