sorry to have generalized on the stable species, I was referring to that "extinct" fish known only in fossils, stone imprints, that turned up in fishermen's nets in south africa. extinction of course in not change for the better
Here is an idea that may widen how you view a process. Rather than thinking in terms of better/worse---good/evil, etc, think in terms of adaptation. Rather than judge the outcome, look and see how that outcome came about.
Better in what sense? Austrolopithecus is extinct, and yet SOME individuals adapted to the changing environment, and that led to us, eventually. Was that a bad outcome? I don't think so. The individuals lived their lives, and their offspring that were able to adapt to changes lived theirs, and our offspring that are fit for the environment will live their lives, and that process will continue until this earth ceases to support life. Is that a worse outcome? Are smaller jaws a worse outcome if we don't need the chewing power anymore, and those resources can be used by our bodies to support other systems that we do need? Will the changes eventually lead to speciation---and in that way---Sapien will eventually become extinct, but we will have lived, and our descendents continue to live, but as a different species? We don't know what pressures will present and how they will change us, but this is not a sad story. This is a wonderful story of life adapting. If Sapien becomes extinct, it does not make the life we have experienced any less valid, and it will make way for a species better equipped to handle the new environmental pressures! THEY could not exist if WE didn't exist, and we are all connected and all play a part in the direction we are moving in.
That said, I don't think we should introduce pressures that we can control to push a species into extinction. For our own sake, we like that tigers roam the earth, so there is nothing wrong with not hunting them to extinction, or destroying their environment so badly they can't exist anymore. We are different in that we can see the outcome of our actions and we can plan to minimize the impact. I would not be sad if bacteria that caused horrible disease became extinct. But I would be sad if tigers became extinct through our actions. It's needless and it deprives us of much. It's something we have some control over.
But as far as ancient species that have become extinct, I don't necessarily view that as a 'worse' outcome, because it was part of a process that brought us here.