People love to carp and criticise here, don't take it to heart. The good news is your product is impressive, the bad news is you're not great at selling it as yet, and your target market is not clearly defined.
I found the article really interesting, because it highlights what is clearly a huge gulf between what you expected of YC, and how they behave. You were looking for validation of what you think is a great idea, and to discuss an idea with people who have spent a long time thinking about it and perusing your carefully prepared documents. They don't really care about your idea, they care about you, how well you can sell any idea to them, how well you can sell yourself to them (and by extension customers) in limited time, how you deal with pressure, how much contact you have had with customers, and how you plan to make money. You didn't have convincing answers to those questions, because you were expecting entirely different questions and an impressed audience. YC are not even really interested in your idea, they're interested in whether you can execute. That's probably because most ideas do not survive contact with the harsh reality of customers and the market, but companies do if they can adapt.
In this sense YC is behaving far more like a potential customer of yours than you might imagine - most customers spend about 30 seconds evaluating your product, and if you can't sell them in that time, you have a problem. Most customers will never read your sales docs or understand your product at first, they might read the home page if you're lucky. From a customer point of view, there is a fundamental problem with your idea which I think you're going to have a lot of trouble with:
Who could have developed a new multiplatform programming language with a blazing fast virtual machine?
You're asking people to build a business on top of your platform and a new language. There are a lot of reasons why that's a terrible idea for customers (even if it is a great thing for you), but foremost among them is lock-in. This is not really a technical problem, it's an issue of trust, and these decisions are not even often made on a technical basis. IMO you need to open-source your platform (get rid of trust issues), show customers everything, and make money on support/bespoke development if the platform is good enough to actually attract users (that'll be a very tough sell, and not one based mostly on technical concerns).
Thanks for posting and I hope any criticism you find here will be useful to you.
I think the post above by <grey-area> is on target. I suspect there is a large market for very easy-to-use app building environments (though, because I know how to code and like doing it, I don't know what the competitive landscape is like).
I remember seeing Steve Jobs giving demos of Interface Builder at NeXT -- hey, drag and drop connections between objects! -- and, years later, nobody has solved it yet.
But as <grey-area> says, there may be many reasons why people could be reluctant to switch to your environment. You created a new programming language? I don't care about programming languages as much as having a good collection of libraries -- will I be able to find or convert the ones I need? How about the equivalent of ones like Beautiful Soup, or PIL, or even massaging UTF-8 strings? For reference, CPAN has over 144,000 Perl modules available.
Do I need your build servers to create an app, meaning if your company goes out of business, I'm out of luck? If Apple changes APIs, how long until you support them? Etc. Open sourcing will help.
I understand you're pre-release, and that the site is a placeholder. But you may want to address some of these questions in a FAQ. In any case, I applaud your effort. You're trying to create something new and powerful. Very few people have the courage and fortitude even to try.
UPDATE: I watched part of the video and it seems very GUI-based, so my question about programming languages and libraries doesn't seem relevant.
I found the article really interesting, because it highlights what is clearly a huge gulf between what you expected of YC, and how they behave. You were looking for validation of what you think is a great idea, and to discuss an idea with people who have spent a long time thinking about it and perusing your carefully prepared documents. They don't really care about your idea, they care about you, how well you can sell any idea to them, how well you can sell yourself to them (and by extension customers) in limited time, how you deal with pressure, how much contact you have had with customers, and how you plan to make money. You didn't have convincing answers to those questions, because you were expecting entirely different questions and an impressed audience. YC are not even really interested in your idea, they're interested in whether you can execute. That's probably because most ideas do not survive contact with the harsh reality of customers and the market, but companies do if they can adapt.
In this sense YC is behaving far more like a potential customer of yours than you might imagine - most customers spend about 30 seconds evaluating your product, and if you can't sell them in that time, you have a problem. Most customers will never read your sales docs or understand your product at first, they might read the home page if you're lucky. From a customer point of view, there is a fundamental problem with your idea which I think you're going to have a lot of trouble with:
Who could have developed a new multiplatform programming language with a blazing fast virtual machine?
You're asking people to build a business on top of your platform and a new language. There are a lot of reasons why that's a terrible idea for customers (even if it is a great thing for you), but foremost among them is lock-in. This is not really a technical problem, it's an issue of trust, and these decisions are not even often made on a technical basis. IMO you need to open-source your platform (get rid of trust issues), show customers everything, and make money on support/bespoke development if the platform is good enough to actually attract users (that'll be a very tough sell, and not one based mostly on technical concerns).
Thanks for posting and I hope any criticism you find here will be useful to you.