I agree that the characters, in particular Pip, take part in emotional more that physical journeys; although Pip's travels to London would have been seen as quite an adventure at the time. I think Magwich, Estella and Joe go through emotional journeys which change their lives. Also Mrs Joe suffers violence after years of wielding Tickler and her scold's tongue.
Other editors are correct in pointing towards the way that the story charts a journey of experiences of many characters, not just Pip, although clearly the narrative focuses most extensively on his moral development. Even Magwitch himself could be argued to grow and mature from his experiences, dying at last a man at peace with himself. Certainly, however, the central focus of the story is Pip's development and increased awareness of his actions and choices and how they impacted both himself and others.
Great Expectations is indeed a bildungsroman; it is Pip's search for a father and his return home as the prodigal son; it is his dragging of the figurative leg iron of guilt until he at length reaches his sense of self by helping others and by ultimately returning to the forge; it is Pip's growing awareness of the unfairness of social class that fauns and flatters an eccentric woman, but condemns a good man who has had the misfortune to have been a gamin of the streets. Along this journey, also, the reader obtains insight into the egregious justice system of England.
There are others who take the journey of experiences as post #3 mentions. Certainly, Miss Havisham does grow as a person; Estella comes to a realization about herself and about Pip; even Herbert Pocket reaches a point in his journey in which he acknowledges his faults and learns from them.
You can argue that any book is about experiences and their consequences. However, I suppose you can say this is particularly true of this book. Other posts here have focused on Pip. I would suggest you look at Miss Havisham. Her life is solely defined by one experience and her reaction to that experience. Her reaction goes on to have a tremendous impact on both Pip and Estella. In this way, you can argue that the book is very much about experiences and people's reactions to them.
Great Expectations is about growing up, and about experiencing class differences for the first time. Although Pip has experiences, they are not the kind of adventures you'd find in some books. Most of them have to do with interacting with people, learning about how the world really works, and experiencing love. There is some adventure when Magwitch returns, but most of it is about learning how to deal with people.
Great Expectations presents us the reality of life in all kind of class in the society. It depicts a typical life of a happy person even without the resources. Happiness of that person comes from his being fulfilled in life (example is Joe). Love is also a big factor of happiness. The decisions of each character (example Pip) to do something wrong or something right led them to their present lives, whether a miserable life or a happy life. In addition, it also shows the other side of a typical rich and unhappy person. Though you have everything, but because of the wrong decisions in life, that person is totally unfulfilled and unhappy. The present conditions of their lives are the result of their decisions in the past, whether it is a big or small decision.