Subject: Re: Limits, We don't have no stinkin' Limits
I suspect reintroducing a species would disrupt the natural balance of things, especially if the species has been extinct for tens of thousands of years (whatever the time span). The reintroduction would likely lead to to things such as the spread of diseases humans may not have ever been exposed to, etc.

Perhaps the focus should be on preventing a species from going extinct in the first place (but I'm not sure if I completely agree with that either). If Mother Nature is behind the extinction of a species, I'm inclined to be "okay" with that and move on.