Opinions change with time - that which is viewed as brilliant today may be viewed as wholly trite and/or indescribably horrid tomorrow. The opposite is also true – that which is viewed with derision at one point later very well may be confirmed as pure genius. It is for that reason that one can't, strictly speaking, mock The New York Times for its negative review of Butch Cassidy and the Sundance Kid upon its initial release in 1969.
In said review, Vincent Canby writes that the film "is very funny in a strictly contemporary way." Of course, it is impossible to watch the movie now, 40-plus years later, and not laugh. Canby also writes that within the work "you keep seeing signs of another, better film," and while Goldman acknowledges in his book Adventures in the Screen Trade that there are some problems with the script, the idea today of asking for a better version of Butch Cassidy and the Sundance Kid is vaguely ludicrous (a project I did in graduate school promoting a remake and explaining how I was going to "fix" the film notwithstanding). In his closing Canby states that the stars of the film, Paul Newman, Robert Redford, and Katharine Ross "succeed even if the movie does not." Again, while virtually everyone today would agree that all three actors give great performances, there are probably very few souls out there who would suggest that the film – both as a whole and in parts – does not succeed.
Butch Cassidy and the Sundance Kid is not a traditional Western, it certainly follows these men at a time when the Old West was dying if not dead, but it is as good an entry into the genre (providing you don't have a strict interpretation of said genre) as was ever made. It is funny and serious, lighthearted and sad, and features Newman and Redford at their level best. George Roy Hill's direction of Goldman's script shows these two men battling not just the law, but time itself, attempting to relive the good old days that have since past them by. These are men who may be having fun doing what they're doing but still wish that robbing trains didn't require sticks of dynamite.