I am not fully sure if bringing back animals that are instinct, even done so by human actions, would repair the damage we've done. After all, nature has the nice ability to adept to new situations. So the disappearance of the dodo, could be taken up in a different matter, and if we're then to recover the dodo, I deem it very well possible the dodo could then do more harm than good, as nature may no longer take a place for the dodo into account. I think that if it were about bringing back extinct animals we should really keep well in mind what those animals would do if they lived today. Humans already caused a lot of damage by bringing animals to places they don't belong, after all. Perhaps with species that have gone extinct more recently, this may not be so harmful.
The idea sounds wonderful, but there's always a flip side of the coin. Scientists who think they can bring these creatures back, should take that in mind.