That's what market research really is good for. And frustrating potential users to minimize your business risks isn't acceptable, in my opinion. There's always risk involved. That's the nature of business.
It seems like getting people to commit to pre-orders is possibly the best form of market research. You've done enough R&D to get a solid outline of what the product will be, and you're testing whether or not people are actually willing to put money on the line to get ahold of it.
Pre-orders can be an excellent form of market research.