That's basically the point I was making, with each little revamp over the years, despite a few slight and subtle redesigns, everything stayed pretty true and accurate to the original source... really, the only major difference I can tell is that in the Cinar/HBO series, Lulu's personality is toned down a bit compared to say, the original Paramount shorts of the 1940s, or even the original comics of the 1930s, where she's more of a troublemaking brat at times, but I'm sure this is because they didn't want her to be a negative role model for little girls who may be watching.
And again, while not too many people jump for joy over the "teen" or "growed up" revamps, at least most of them stay fairly true to the original sources, and the designs simply look like what the characters may look like as teenagers... this, on the other hand, looks nothing like Lulu, Tubby, Annie, etc, and from what I've read about the manga itself, they don't even sound anything like the original characters.