You have valid arguments, but my point is if you're looking to get outside investment, you need to get used to the idea of your potential investors not signing NDA's. Unless you're God himself, they probably wont sign anything (you are LUCKY to have them look at your venture).

If you have some process/idea that is really as significant as you say, and the barriers of entry to implement it are so low that anyone who simply hears about it could screw you, then you should apply for a patent.