After reading The Blue Lotus as a grown person, the revelations of societal mores and the boundaries of political correctness are really the only thing I can think about.
Herge was quite outspoken and heavy-handed about racism (here toward Asians) yet he still portrayed Asians in a way that would be unacceptable by today's standards.
For instance, Herge's philosophy is quite clear here:
However, in the very next panel, we are following the exploits of this guy:
I'm sure Herge would never have drawn anything offensive if he was aware of it. Culturally, our awareness of race and propriety emerges gradually. It must have been an awkward transition for Europeans to shift their value system away from a colonialist perspective that was something that was less self-centered. Tintin was in the heart of this change. I mean just look at this twenty-something's luggage!
One has to wonder what we are saying now that will be offensive to future generations but don't even get me started on Tintin in the Congo.