Sometimes it is, but consider the possibilities of Vietnamese priests serving the sizable Vietnamese Catholic populations in many larger cities. Similarly, a Latin American priest brought in to serve the Latino Catholic communities would find himself quite at home. Surely, the ethnic communities that these priests went into would be more than happy to familiarize a new priest with American culture. I seem to remember a lot of priests coming from Ireland to the Northwest, which was still considered "frontier" territory for the Catholic church.
Yes, it is pure speculation about women priests, but if married priests are allowed, they might not have to take that step.
Well, now, that's an entirely different proposition. Bringing a Latino in to serve Latinos makes consummate sense.
But bringing a Nigerian in to serve a pasty-faced white Anglo parish will take some patience, on the part of everybody.