In the Spending section, where you can drill into each Category, there's a summary on the right that includes number of transactions, average amount per transaction, etc., but it seems to be missing the obvious one - monthly average for the Category. This would be useful to track Year Over Year as a means to budget more effectively.
For example: in the Groceries category, show the monthly average spent on groceries, maybe even weekly average. Seems like that would be more useful than the average transaction size and number of transactions.