There are two large problematic issues during Pesach, the biggest being kitniyot, aka legumes, but not exactly in the botanical sense. There are non-kitniyot eaters who do eat the derivatives, such as soy oil, though not the beans. The basic divide is between Ashkenaz (European) and Eidot Mizrach (North African) Jews, or those whose paternal lines, ancestors lived in those exiles when the customs took hold.
Ashkenaz Jews are forbidden fresh as well as dried versions of the vegetables such as peas, rice, lentils etc, but the Eidot Mizrach have a wide variety of customs depending on which rabbinic sources they follow. Our Tunisian family members eat all sorts of fresh and dried legumes and rice after multiple checking, while Moroccan neighbors are forbidden rice and some of the legumes.
In recent years there are more and more Asheknazi families who have decided whether from convenience or conviction to adopt Sephardi custom on Pesach. Rabbi David Bar-Hayim of Machon Shilo (no connection to the Shiloh where I live) has been pushing for this unifying move for quite a few years.
The basic premise of Rabbi Bar-Hayim is that when investigating the history of the minhag, custom he discovered that the most prominent rabbis of the time the custom began opposed it. They considered it a mistake. Therefore he considers it permissible and preferable to stop this incorrect practice. The big problem is that he is in a very small minority. It would take the agreement of a number of highly respected poskim, rabbinic deciders to take his very interesting points reality.
G-d willing, all of these divisive customs will soon be history with the Coming of the Moshiach bimhairah biyamanu, speedily in our days...