As for the concern on harvesting peoples' information, we try to be very open about the fact that applications will indeed be made available to founders of YC companies to facilitate employment opportunities. Are you not comfortable with the "all or nothing" nature of that?
Knowing that I don't have to fork out any information visiting "Who is Hiring" makes it a tough sell.
I think there is a question on why here. Lets say you add company job listings: why see them here and not on angellist (shows lots of information) or who is hiring (no commitment) or the companies job page.
The beginning of the page mentions all big name companies which I would already know and would just go to their pages for job postings where I can better prepare my CV. It might be VERY different if the companies here are small and unknown, and are somehow vetted or show unique YC information about them. Angelist is too expensive for a 2-3 man shop just out of a batch.
I guess I picture a YC official page to be about segmentation, not open-wide job listing competition with other big sites.
For example, I would love to know at a glance what the applicants' interests/passions are by sector/product type — in addition to technological passion/experience.
While I recognize that each field adds friction, I'd take a high expected quality (e.g. qualified technical and passion match) candidate over a high volume of candidates any day.
You are engaged in one of the more basic forms of information arbitrage: a "gather info from users and sell it as a searchable database" model. To make this work, your cost of acquiring information must be very low because the incremental value is very low (the value is in the aggregate).
Most startups like this crawl the web or otherwise index their own data from somewhere like LinkedIn because it provides an easier path to mvp/scale, but also because its a balance that HN types will respect: "I did the work finding the information and I can so what I want with it."
Asking users to provide the information that you then sell is shifting the cost of that data acquisition cost burden from you to your users, and is comparatively rather expensive in terms of the currency that you are expecting someone to spend to provide you with value, i.e. time. Its more expensive than passive data acquisition. You are, in a very real sense, charging for your users to access the site.
So when you have a link that says "Sign in with HN and get started" and that link essentially forwards to the order page, and that ordering page is (or looks) expensive, you have some sales work to do beyond "make it a bit cheaper by asking for less" or being open about what you'll do with it. You are doing almost zero sales work on your current landing and ordering page beyond adding a big sign saying "Pay".
Also, something else to keep in mind, how much information you ask for is, again in a very real sense, a form of price discrimination.
Any model which includes an element of price discrimination requires a mechanism to charge different users differently to maximize the overall profit. Otherwise you are facing an existential risk in the form of mispricing risk and have no ability to iterate out of it, because each change you make to the price will shift your entire userbase to people who are willing to pay that price, so you can't learn from it.
Just saying "most things are optional but more is better" actually hurts in most cases because it implies that you are unsure what pieces of data are actually valuable and rather than figure it out and only asking those things, you're, again shifting that cognitive/time cost to your users to figure out. A business with a sign saying "pay as much as you like and you'll maybe get more value out of it but maybe not we don't know either" does not inspire a lot of confidence.
The best companies in the business of arbitraging data explicitly provided by users charge the lowest price possible before they provide value, and then provide incremental value as the users pay more. LinkedIn has figured this out, that's why you can be in the site searching after just a very basic profile, and then they ask for more over time as users are getting value from the lower pricing tier.
By insisting on all or nothing, you are ignoring the lessons learned by arguably the most successful example of active user information arbitrage the world has ever seen.