Not a perfectionist, but this interview with Ned Price of WHE, conducted by none other than RAH, is enlightening re: the previous master. What they've accomplished here is a stone-cold miracle. http://archive.thedigitalbits.com/articles/robertharris/harris082106.html
Again, I don't mean to say that the previous Blu-ray was perfect or left no room for improvement. However, had this remaster not come out, most viewers who might have an interest in watching The Searchers would consider the prior Blu-ray to be good enough for that purpose.
This wasn't a situation where, either 1) the movie never had a Blu-ray release, 2) the prior Blu-ray was an altered cut of the movie or missing important footage, or 3) the previous video master was so abhorrently poor as to border on unwatchable.
The original Blu-ray of The Searchers had a sharp image and was a respectable presentation. It received good reviews when it came out. Sure, someone really familiar with the film might notice that the colors were off, but most viewers would neither know nor care about that.
(Along similar lines, I absolutely loathe James Cameron's fixation with re-color grading all of his movies into teal-and-orange. It drives me crazy to no end. However, I understand that if I show the 4K release of The Terminator to my buddy who's not a videophile and is just a regular fan of the film, he's going to think it looks great. He'll see no room for ever needing another copy of that movie afterwards. Whereas I pine for the day someone takes control of the entire Cameron catalog and properly remasters all his movies without his involvement.)