Oh sure, it sounds like a good idea. But think of all the things we've lost to natural selection:
According to Notornis, a peer-reviewed journal for the study of birds, Haast's eagle is "the largest eagle known to have existed." Ate a diet consisting of moas, which were twelve-foot tall flightless birds. Its bones were first discovered by German geologist Julius von Haast, who, lacking a German equivalent of the English phrase "hella ginormous", named the bird after himself instead. Between its size, and its natural habitat of New Zealand, Haast's eagle was the real-life version of Gandalf's Eagles in Return of the King.
Once the most common bird in North America. Its flocks were reported to be a mile wide and take several hours to pass overhead, which is why 19th century seven-day forecasts alternate between pictures of suns, clouds, lightning, snow, and passenger pigeons.
Commercially hunted on a massive scale until they went extinct. The current figure of speech "like shooting fish in a barrel" developed from the pre-Civil War figure of speech "like shooting a giant flock of passenger pigeons and managing to hit one".
The last passenger pigeon, Martha, died at the Cincinnati Zoo on September 1, 1914, having spent the preceding years writing memorial wall posts on the Facebook pages of her 7,825,623 dead passenger pigeon friends.
A Pleistocene ground sloth that was the size of an elephant. Despite its size, still cute. In the Pleistocene, when you won a carnival game, the giant stuffed animal you won for your girlfriend (but still had to carry around for her for the rest of the day) was a stuffed megatherium.
Darwin found some bones from a megatherium skeleton in South America in 1832. This was yet another milestone in his complex, diabolical plot to fool the schoolchildren of Kansas into forgetting religion.
Current estimates say that this shark of the early Pleistocene was 40-50 feet long and weighed 48 tons. Megalodons needed massive meals to keep their massive selves alive, so scientists guess that they either ate whales or Denny's. So scary they make the Great White Shark look like Abigail Breslin.
The megalodon's body was mostly made of cartilage, so the only fossil remains are jaws and teeth, like these right here OH MY GOD LOOK AT THOSE HUGE TEETH.
Cro-Magnons: NO LONGER PINNACLE OF EVOLUTION
There are all kinds of situations in daily life where it would be really nice to look relatively brilliant. With a few Cro-Magnons in the workplace, that's easy. Sure, you didn't make a new pot of coffee after you took the last of it, but at least you weren't the guy who heaved the copier out a window when "it make bad light and monster noise".
The Species That Would Have Cured Cancer: EXTINCT
What, you haven't heard of it? Of course you haven't. It went extinct before anyone knew about it because its entire rainforest home was slashed and burned, just like thousands of other species we never even discover in the first place.
Every Dinosaur That Ever Lived: EXTINCT
I know, I know, "they evolved into the birds of today". Do the birds of today make me feel like Sam Neill in Jurassic Park? No, they do not.