Personally, I don't think the USFSA should go the route of the French or Russian federation, where Piseev or Gailhaguet or some committee meeting behid closed doors can just send the skater whose coach has the most political pull within the federation.
I would not like to see a system where the committee can just say, you go to worlds, you stay home, on the basis of personal whim.
The advantage of the winner-take-all National Championship is (assuming unbiased judging) that it is cut and dried. The skaters know exactly what they have to do to make the World team, no politicking in the hallway.
However, a point system in which a skater gets credit toward making the world team by virtue of placements at international competitions would be OK, as long as the criteria are precisely delineated in advance and not dependent upon being the current darling of the powers that be.