Anvilicious: According to this article, the franchise was meant for kids who grew up from late 70's to 80's, showing them the struggle that their parent's and grandparents went thorugh after World War II.
Archive Panic: And how! The series has 31 entries and each of their episodes are around 25 minutes. Then, there are A Dog of Flanders and 3000 Leagues in Search of Mother movies.
Broken Base: Some viewers think that the entries involved with Isao Takahata or Hayao Miyazaki are the best in the series, others think that the shows from late 70's to 1980's are the best, and there are some people who love the series because of Nostalgia Filter.
Gateway Series: The franchise introduced some obscure or not so well-known novels such as A Dog of Flanders, Southern Rainbow and Romeo's Blue Skies.
Germans Love David Hasselhoff: Look at the Wikipedia page for at least 60 percent of these shows in Italian, French or Arabic and they'll likely be twice as long as the language of the page you were previously reading.
Slow-Paced Beginning: The franchise suffers from this for those people who are not interested in settings, additional back stories and characters who are not originally appeared in the novels. Each of the anime takes around few episodes to see new characters and to pick up the pacing of the plot.
Tough Act to Follow: The rest of the entries after "Anne of Green Gables" never managed to receive the same level of acclaim.