- Older fanfics violate canon much more blatantly in a lot of ways. While there's plenty of exaggeration, mistakes, and stupidity even among the better modern stories, an awful lot of it is basically hewing to established fanon stereotypes that aren't really canon, but aren't that far off either. Whereas looking back at older fics that I really liked, I see a lot of what can only be considered errors -- stuff like Ranma using a Hiryu Shoten Ha on a wooden post in Careful Destiny.
- Older fanfics seem to hew much more closely to the spirit of Ranma 1/2 as authored by Rumiko Takahashi. By which I mean, there's a lot more emphasis on comedic martial arts challenges and storylines, on stories that could be credible continuations rather than abrupt departures from the status quo, and on the fiances as a core of the story rather than a problem to be solved or at least attacked.
- Portrayals of Ranma felt substantially more genuine in the older ones. Especially when it comes to his many, many decision-making weaknesses. Which isn't to say that newer ones weren't fun to read, but among the more modern fanfics I've enjoyed, an awful lot of them featured a Ranma who rapidly changed from the canon Ranma... if he didn't start the story substantially changed in the first place.
I'm curious what sort of observations everyone else has on modern vs old Ranma fanfiction... and are the trends in the new better or worse than the old? Myself.. I think I actually prefer the new cliches to the old ones.