Considering we don't know all of the circumstances behind the delays, it's plausible that it's impossible to set a date. If there is some underlying issue with 4G (or something else) that we've not heard about, it is certainly within Verizons best interest to not set a date for release. Again: the only people who know and are complaining are the enthusiasts, which are a tremendously small percentage of Verizons customers.
As much as it sounds like I'm defending Verizon, I'm really not. As I've said before, I too am less than pleased with the release thus far. Everyone just needs to stop viewing this situation from only the enthusiast/consumer side though and look at what Verizon is possibly dealing with to get this phone to the market.