We obviously need custom categories, however any category must be manageable. If a transaction is moved out of one category into a new category you need to ask if ALL transactions of that type AND in the same category need to be re-categorised in bulk OR is this a one off move.
So we can gradually get the categories to be meaningful to our individual lifestyle, which is obviously constantly evolving.
Hope you get the idea. If not please let me know if you agree that categories are one of the most compelling features to develop working budgets - but as yet they are very limited and delivered as one size fits all.