The main theme of Girl Meets World is on girl Riley and her journey towards womanhood in general plus a side plot in sisterhood with her best friend, that blond girl who I think is a singer musician.
The main theme of Fuller House is focused on the three mothers finding love. It deals with many different things. But a major theme and the main story arch throughout all the seasons is related to dating and marriage. I found Fuller House to be romantic, funny, interesting, emotionally moving at times, very surprising and exciting at times more so than Girl Meets World.
The style between the two shows are pretty different. Fuller House is a kind of show that has more variety than Girl Meets World, generally speaking. So, you may sometimes find different styles in different episodes of Fuller House. So, I enjoyed watching it because it was always full of surprises. Girl Meets World was generally more predictable. But I do love both shows a whole lot. But I just love both shows in different ways. Because they're different but also similar in some ways.