It's a great film, it's not preachy at all, for those complaining its feminism and all, Barbie doll, has been, in fact, made in 1959 to break the old long standing tradition where female role in society is only to become a mother, Barbie inspires that woman can be a mother as well as everything she wants, a pilot, president, CEO, astronaut, you name it. It actually is a pro-mother film.
Some people may be offended by how Barbie treat Ken in Barbieland, but remember that's how little girls interact with little boys in term of sharing their belongings, in this film, that is dreamhouse, car, etc.
Barbieland also seems matriarchy, but remember the land is actually created to encourage little girls imagining their career and purpose in life, so don't take that into account to devalue Ken. I also personally don't find any dialogue which is demeaning to Ken, in fact, in the end, Barbie apologizes to Ken for how she treated him and asked Ken to also find and understand himself and his purpose in life, and that he should not rely onto Barbie, which by the way, the first purpose Ken is made for as toy. I think that message is beautiful, that scene really represents how little girls and little boys grow up.
However, i can see some conservatives, especially in the US, couldn't stand that, and will mostly be offended by everything in Barbie film, because after all, they couldn't stand of anything beyond their perspective in this life.