Hi,
Question 1: how can we increase the productivity of our idea generation (how to increase the ratio between good ideas and pointless ideas)?
Question 2: what are good (reliable) methods of estimating market size?
Question 3: How to predict people's reception of a new (or previously fringe) product? And can we control their response?
Question 4: how to conduct your first approach to a potential buyer of your idea, or a VC?
Would learning copywriting help in such pitches? Or would it hurt it (investors are not general public, thus i presume they might be turned off by ‘’salles’’ approach)?
That was a monster post and a lot to digest, but I've narrowed down the questions to these and I'll answer best I know.
1) The only way to really know if an idea is good is to test it. The internet is great because we get faster feedback than from anywhere else. What you can do is setup a simple landing page that offers what you're thinking of selling, then have people optin to a waiting list. This will tell you if there are people interested enough to take at least the action of getting on a list to get it. If response is poor, that will usually indicate something not worth pursuing and you can discard it.
2) You want to look at the size of lists of people who have bought in that market. For this, Nextmark is your friend: http://lists.nextmark.com/ - Search on what you want to offer and Nextmark will show lists of people. It includes buyers lists of specific products and how big they are. You can see the potential of a buyers market size for free this way within minutes.
3) Anybody who says they can predict people's reception of a new product is a liar. You can NEVER really know without testing. Large companies try to predict with sampling and controlled tests but the only real way to know is to actually take action on it. You can try to survey your potential market asking how they'd receive it but that data won't tell you how many people would actually take action. I'd refer you to answer #1 - you have to actually test the market's response.
4) Buy and read the book "Pitch Anything" written to address specifically what you're trying to do here. It teaches great salesmanship, which is essential to good business anyway.
Last question about copywriting - If you start to learn copywriting what you'll find is that it's just salesmanship in writing. If you're a good salesperson, the person you're selling to won't even feel like they're being sold to. So learning good salesmanship and good copywriting can only ever help you. If you learn BAD salesmanship and copywriting, then it doesn't matter what you try to promote, it'll fail. So learn GOOD salesmanship and you can pitch anything to anybody without anybody taking offense or feeling 'sold' to.