The March Hyde stands out in a crowd and would attract immediate hostilty. The Tracey Hyde looks human enough to pass in a crowd. Also his Hyde was more of a personality change not a physical transformation.
The March Hyde has an iconic makeup worthy of any of the Universal monsters of that era..Tracy looks a bit disturbed but that's all..a visitor to the set at the time of filming couldnt tell whether he was playing Jekyll or Hyde. Im sure there was no difficulty when March was on set as either character.
You're right, the [point in the March hyde is hard to accept as someone who could walk i to a bar without an immediate "WTF IS THAT?!?!" response.
As shown in the film, there usually was that kind of response when others viewed March's Hyde..the whole point was the extreme in personalities, not bouts of manic hysteria as shown in the 1941 version(which is almost a scene by scene weaker remake with big names) of the 1931 version.Part of the reason that Tracy's Hyde is not more horrific in appearance is that he refused to wear any kind of feature altering makeup. Hyde, as described in the book, was certainly bizarre in appearance and didnt look like someone who was just plain nuts as did Tracy's version, he was distorted and twisted in appearance. There have been many Mr.Hydes, the March one certainly is iconic, hell, even John Barrymore's is pretty memorable, but Tracy's doesnt even scratch the surface as far as being an iconic one.