You bring up a good point – that being – if categories are shared across accounts, they *should* also share the amount and contributions to it. In fact, this is the best way to budget. You budget your money based on your income, not based on the number of accounts you have. Our goal is more to encourage good personal finance, less to have a flexible tool.
The only visual problem is… now we have categories that will say you have, say, $100 spent, but its not clear where its been spent if that spending is not in the current account.
The planned aggregate account view will take care of that, but viewing a specific account will have its drawbacks.
We had thought if having the category side bar be expandable to the right, show more details about your plan vs actual spending. We could simply have 1 column for plan, and x columns for actual, 1 for each account and show its contribution to that category’s activity.