If you're still in a development funding stage, then you're probably dealing more with angel investors or friends and family and not yet at a venture-capital stage. These can hamper reputable VC's ability to make connections and get things done. If you can't trust a VC with your business idea, look for a different one. That doesn't mean to stop listening. Just have a little more faith and trust your judgment.
Every business venture has some risk.
Even your personal conversation and acknowledgement by the gatekeeper is always better than submitting plans cold. Like all consumers, a VC's impulse needs to be captured at the point of purchase. If there is steak, make it sizzle-that's going to attract. Depending on how full the VC's pipeline is, the process can take anywhere from two to five weeks to get any substantive feedback. A follow-up after two to three weeks is appropriate just to stay on their radar screen.