Lookup / Rollup properties for Relations

Currently, when an Object links to another Object via a Relation, we cannot display or use properties from the linked Object directly within the current Object or layout (e.g., viewing a Client's "Email" or "Phone" inside a "Project" object that is linked to that Client).

I would like to see a Lookup / Rollup property feature.
Specifically, this would allow us to:

1. Select an existing Relation property on an Object.
2. Pick a target property from the linked Object type (the mail or phone from the contact linked; the category from a parent project; summing up task hours on a goal; ...)
3. Display that target property value automatically inside the current Object, Object List, or Table View.
4. (Optional) Apply aggregation functions (e.g., Count, Sum, Average) when referencing multiple linked Objects.