Having hunted all over the country I can tell you with no doubt whatsoever that whitetail and all the other deer family absolutely does have different flavors. They can have different flavors not only from different states but even different counties. What they are feeding on greatly dictates what the flavor of the meat will be. As far as the "gamey" flavor, a deer that has ran hard recently will have a buildup of lactic acid. It isn't the adrenaline as adrenaline has no flavor whatsoever. Lactic acid has to have a little while to work it's way out of the muscle tissue before death. It can't really be "hung out" completely, though if the deer is aged a few days (hung) it will dissipate SOME but not a lot. There are also many other factors to that gamey flavor, in bucks especially, but most of it stems from lactic acid and poor preparation and handling of the deer to begin with. BUT a deer that has been ran very hard with no cool down time before death absolutely does have a different flavor than one dropped in it's tracks. How different would be based on how much lactic acid buildup there was in the animal before death. For example, my dad was a huge bow hunter. He would rather bow hunt than any other weapon choice when it came to deer hunting. We would take deer off the same property, same fields most times, and the deer he would take with bow, 90% of the time, would have a stronger "more gamey" flavor than the deer I would take with a high shoulder shot dropping them right there. I say 90% of the time because there were times his bow kills wouldn't run far enough to build up any lactic acid to do anything.
Hormone release can also give meat a strange flavor. There are some that say fear will have a distinct result on meat flavor especially in lamb some say.

As to hunting over dogs. To each their own. I don't care for it myself. My styles of hunting make it impossible for me to hunt areas where it is practiced. Deer are just too jumpy and I have seen time and time again where so many dog runners of today have absolutely no respect for property lines. That is one of the main reasons the practice is so hated. I know several people that live in a couple of the states that allow it that are always having their hunts interrupted by dogs on their property that the "hunters" sent in to chase the deer off their property pushing the deer to them. It's a despicable thing to do and done all too often.