Hardly overboard. Even in an environment full of unrealistic things, when one encounters something that they can clearly relate to something else in reality, they expect that to behave in a very similar manner. You can't really have any expectations for the speed of guar, kagouti, and nix hounds, but as soon as they replace those with wolves and deer, we have established expectation on the behavior of the animal and thus 'unrealistic' doesn't seem acceptable in this situation.
Of course, the design problem is that the player does indeed run unrealistically fast. Most people don't want to walk at a natural pace, even if it's at what is a natural run pace. Then there is the part that people expect to run fast from the start, and then very very fast by the time they get things like speed and athletics up. There really is no other option. Either they pump up the environment to the point where people need to go slow, people get very annoyed with walking slow in an environment that isn't very interactive, or you speed up animals to the point where everyone is running unnaturally fast.
I'd chalk it up to nature of the beast.