The HOGAN'S HEROES pilot is interesting because of so many other differences from the series proper, like Burkhalter being a Colonel instead of General, or all of the prisoners being part of Hogan's team and not just his usual four comrades, and most vexing of all: Carter is just passing through on his way back to London while Hogan has a Russian tailor named Vladimir.
And here's a little bit of trivia for you: did you happen to notice Newkirk talks a little differently in the pilot? Richard Dawson wanted to stray away from the American stereotype that all British people have a cockney accent, and wanted to give Newkirk a Liverpool accent, thinking American audiences might like hearing a different British dialect unlike what they're used to, but he was advised against it on the grounds that it was hard to understand what he was saying, so he relented and gave Newkirk the over-the-top cockney. Then Beatlemania swept America, and nobody seemed to have a hard time understanding them.
And I see what you mean. You mention how the Norman Lear shows like ALL IN THE FAMILY, SANFORD AND SON, THE JEFFERSONS, etc. pretty much purged previously popular 60s sitcoms, but when you think about it, the fantasy sitcoms of the 60s kind of did the same thing to the more wholesome, domestic sitcoms like LEAVE IT TO BEAVER, DENNIS THE MENACE, and others. The fantasy sitcoms like BEWITCHED, I DREAM OF JEANNIE, THE ADDAMS FAMILY, THE MUNSTERS, and others were really, really big in the 60s, because they were so way out and kooky that they offered TV viewers an escape from the tumultuous realities of the world around them like the Civil Rights movement, Presidential assassinations, and things like that, and that really makes a lot of sense.
I used to hate-watch HOGAN'S HEROES, because I found the show to be really silly, fluffy, and trivialized war and Nazis too much - I mean, when you compare it to a masterpiece like M*A*S*H, it's like trying to compare, say, Dora the Explorer to SST. But, the more I hate-watched Hogan, the more it grew on me, and I have to say that my previous hatred of the show was actually unjustified: I saw many of the earlier episodes, where the humor was a lot more broad, silly, and even cartoonish at times (like GREEN ACRES, but in a German prison camp), but I eventually saw that as the series progressed, the humor matured a little - maybe not to the level of sophistication as M*A*S*H's humor, but there is a noticable difference in the humorous tone when you compare episodes from the first and final seasons. And as for trivializing Nazis, that was something that even the Jewish actors portraying them were okay with: Werner Klemperer (whose family fled Germany as Hitler was coming into power) even stated that he wanted Klink to always look like a fool, and always be thwarted by Hogan's gang; John Banner (who fled Austria) even said he felt a lovable dumbkopf like Schultz represented the little bit of good found in every generation (and even remarked, "Who better to play Nazis than we Jews?). Robert Clary is even a Holocaust survivor - as an entertainer, he always wore sweaters or long sleeves to hide the serial number tattoo on his arm. The only one who took issue with the show was the actor who played Vladimir in the pilot: he felt making fun of Nazis was insensitive and opted not to sign on as a castmember when the pilot went to series, hence why Carter was brought back and retconned as one of Hogan's men.