Sam, you nailed what I still have problems with about John Ford, his desire to be complex while always copping out to the audience friendly solution. Maybe you'd be better off with Howard Hawks stuff like Red River.
Haven't seen that for awhile, have you?
I think the ending of The Searchers
is fully earned, both in its happiness and its complexity. I'm surprised that you'd read it as Wayne being able to reside in the safe comfortable place in the end, considering he explicitly does not
get to return to the home in the final shot, but is instead left outside the family unit.
I also certainly don't think the film ever justifies the racism the white people show against the Indians, which you characterize as "The film slid(ing) back into the easy place where it becomes clear to denote good and evil, right and wrong and see that in the end, those Comanches had it coming and by golly, good thing those cowboys showed up when they did." There are evil Indians to be sure, but good ones as well, same with the white people.