Fish,
You ask a great question, and part of the reason that you havent gotten the answer you deserve is because the conversation got sidetracked, and alot of that is my fault. So you have my sincere apologies...
You know, I used to be a believer in the flood, and actually taught it while conducting book study, and of course going to door to door, and fought for its defense in High School. I began to have some problems, like you, over the idea that God could just wipe everyone out 4300 to 4400 years ago. Needless to say, I dont believe in the flood anymore, and part of that is because of the bible, but most of that is because of an objective and real look at the world that we live in, and the actual logistics of the flood. Here is some information that helped me, maybe it will help you decide what you think...
(1) Within the bible, Cain is believed to be the father of the group known as the Kenites. Tracing their ancestral history leads to some of Cain's offspring. You can find mention of the Kenites throughout the Old Testament. Numbers 24:21, Genesis 15:19 and several others. The thing about this is, that these ancestors of Cain are all around after the flood. I always thought this was kind of odd, because it would mean that this group would have had to reform after God destroyed that system of things. The only ones around to teach that would have been the 8 faithful persons that God had just saved. Seemed like kind of a stretch.
(2) Running along that same line of reasoning, the 8 faithful men and women would have had to teach all of the false religions of Egypt, and reestablish many of the gods worshipped by the Sumerians and the Accadians, that all existed before the chronoligically assumed date of the flood, as well as restablish such cities like Ur, which were hotbeds of what would have been the type of false religion that Jehovah would have been trying to destroy in the first place. There were only 8 people that would have been around to teach all of these things. Did the 8 people that Jehovah saved reteach all these falsehoods so well that entire cultures reestablished themselves around them?
(3) As has been discussed in the thread at length, another assumed purpose of the flood was to wipe out the Nephilim. Numbers 13:33 indicates that clearly didnt happen. The only way that it could be possible for the Nephilim to reemerge would be if the 8 that God saved had the genes for the Nephilim themselves, which we know is not the case.
(4) To this day, shipbuilding technology does not exist to construct a wooden ship to the specifications that the ark was supposed to measure.
(5) If the water existed in the form of a vapor canopy above mankind, as the bible does suggest, and the witnesses argue for, no one would be able to live. The reason behind this is atmospheric pressure. We all have approximately 14 pounds of atmosphere pressing down on every square inch of our bodies. This is the weight of the air itself as the gravity of the Earth pulls the atmosphere towards its center. This constant pressure is what causes air to travel in and out of your lungs when you flex and contract your diaphragm. If a spherical shell of water 10 feet deep was placed around the earth everyone on the surface would feel the pressure of being ten feet under water. That is because the weight of the water would press down on the atmosphere, which would then press down on you. If that canopy is going to contain enough water to cover the tallest mountain, or even a small fraction of it, it would have crushed everybody. If 1% of the water in the flood came from the canopy and it could cover the tallest mountain that would still be 290 feet of water. No one could survive that. And why would God create a world like that where that was the way it was supposed to be? Unless he planned for the need to kill everyone by a flood, which would make it hard to justify the emotion of "regret" regarding making mankind. And if he changed mankind to readapt to their new environment, then he would have also had to change the animals. It just starts getting kind of crazy. You see what I mean?
(6) Additionally, I dont believe in the flood anymore because there really isnt any evidence of it, actually overwhelming evidence against it. As Mary correctly pointed out, we would see a nearly uniform ratio of fossilization of marine and terrestrial animals covering the entire globe. Also, there would be a uniform sedimentary layer covering the entire globe. There are also trees that are still alive that are over 5000 years old. Would these have survived the flood? Additionally, there is a lot of worry today about melting icecaps lowering the salinity in the oceans and how that will effect our ecosystems, a small change could effect our weather for years. What would have happened in the case of a global flood? How did Noah gather all of the animals? There are millions of species. He would have had to load several dozen pairs per second, nonstop in order to get them all in there, and to top it off, he would need to feed them all for a year. Many of the species he would have had to save only consume live, or recently dead, flesh. Some only have the capacity to consume rotting tissue. How were they fed? What about the bugs? Where was the greenhouse to keep the vegitation fresh for all of the herbivores? Many herbivores supplement their digestive systems with the enzymes contained in the vegitation that they eat, they can not have rotten vegitation. Where was all this held? You can get on a rant and really keep going with this...believe me, I have!
There are a whole slew of other reasons....but I gotta get back to work! Please let me know if you want to hear more. Anyone else, please feel free to chime in! Anyone who cares to disagree, please feel free. A healthy dialogue is always good...
Oh, and I got the name Slacker because I never take a break, and I really dont sleep! Its a joke...
Take care.