Hey, just playing devil's advocate here. Some banks come pretty close to what you're asking for. I go to a small, community bank in flyover country that uses Jack Henry as a SAAS for its online services. Most of the things you asked for are already being offered.
> I should be able to partition my money into several lightweight accounts - one for groceries, one for home expenses, investment, etc
You can open multiple checking accounts at most banks. I've made partitioned checking accounts like this before.
> automatically have fractions of my deposits sent to those accounts so my budgeting and money management are handled without any effort on my part.
Money transfers can be scheduled but they're usually by set amounts instead of fractions (e.g. add $100 on the first of the month). I use this myself.
> I should have lightweight cards available for each of those accounts with online card management (request/terminate cards, track per-card spending)
Should be able to open debit cards for each account but you'll probably need to be in person to request/terminate them. Maybe you could do it over the phone by authenticating yourself, not sure. I haven't heard of per-card tracking but at least you know what you spent on your card.
> multiple cards per account so I can give my wife full use of "grocery" card
You can tie multiple debit cards to the same account for a husband and wife. Try explaining what you're doing and a banker should set that up for you.
> alerts/notifications when I am spending too much in an account/not efficiently allocating the full amount/potentially using a card improperly
There are account alerts that can be set up for exactly this. I have it shoot me an email with the alert message when something gets triggered.
> financial projections
Account history can be downloaded in common formats like csv. There are already tools you could use to create the projection and do fancy data visualization things for yourself. You could scrape your account data periodically using your online banking credentials. Might be dangerous to automate though.
> I should be able to partition my money into several lightweight accounts - one for groceries, one for home expenses, investment, etc
You can open multiple checking accounts at most banks. I've made partitioned checking accounts like this before.
> automatically have fractions of my deposits sent to those accounts so my budgeting and money management are handled without any effort on my part.
Money transfers can be scheduled but they're usually by set amounts instead of fractions (e.g. add $100 on the first of the month). I use this myself.
> I should have lightweight cards available for each of those accounts with online card management (request/terminate cards, track per-card spending)
Should be able to open debit cards for each account but you'll probably need to be in person to request/terminate them. Maybe you could do it over the phone by authenticating yourself, not sure. I haven't heard of per-card tracking but at least you know what you spent on your card.
> multiple cards per account so I can give my wife full use of "grocery" card
You can tie multiple debit cards to the same account for a husband and wife. Try explaining what you're doing and a banker should set that up for you.
> alerts/notifications when I am spending too much in an account/not efficiently allocating the full amount/potentially using a card improperly
There are account alerts that can be set up for exactly this. I have it shoot me an email with the alert message when something gets triggered.
> financial projections
Account history can be downloaded in common formats like csv. There are already tools you could use to create the projection and do fancy data visualization things for yourself. You could scrape your account data periodically using your online banking credentials. Might be dangerous to automate though.