Cool.

Imagine if you introduced massive numbers of Bengal Tigers into the Siberian Tiger population. The two sub-species began inter-breeding on a large scale. Several generations down the road, there are no more black and white tigers in the population, nor are there any spectacularly colored Bengal Tigers. You just have a faded, off color Sibengal population that is largely unremarkable.

By introducing diversity, you've created a situation that eventually reduced the overall diversity in the Tiger population. By removing two distinct sub-species with unique traits and created one bland species. Now do it with every sub-species until every Tiger is exactly the same. No more Siberian, Bengal, Sumatran, Malayan, or Indo-Chinese Tigers (which are diverse enough to be independently recognizable. Instead you just have "Tiger".

The Tiger would probably be really good at golf, but people would eventually hate it.