Tim Rivelo Refusing to implement a brilliant feature "because someone did it before" is imo the most stupid reason of all to not do something. Now that other party is directly dictating what you can and can't do. Just be independent, think for yourself and be brave enough to admit it when a competitor does something brilliant.
And that balance graph the Rabobank app has (and the "balance after transaction" field as well) is pretty nice. They are probably not patented, people want them, just implement them if you can't think of anything better yourself.