Two ways of looking at it I guess.
We come to the same desired result from different angles. You wish to create one monolithic gene pool by interbreeding as much as possible, whereas I wish to create a homogeneous population by isolation. Either way, the result is the same in the end, one population.
I happen to think that a uniform gene pool would be the best way to go. It would cause far fewer problems over the long run such as different blood types, dental problems, and a host of other problems. You prefer the scatter gun effect. Like an alchemist madly mixing and matching compounds in the hope of creating his philosopher's stone. Both approaches have their advantages and drawbacks. I guess it's just a matter of style and taste.