I agree with you, I too have had people that say He cannot return until the gospel has been preached to the whole world.  I do like your response that you gave, and I am sure it made some think about there own stance.  I do believe that the gospel will be preached to the whole world, but by the 144,000.  Let us continue to have the words to speak to others that come directly from the throne!  They are the words that will bring the most fruit!

Dave