The aerodynamic features of the RB7 that resulted in its dominamce are; What i deduce at least:
The fundamental chassis design.
The splitter channels.
Front wing design.
The holes that are situated along the gearbox.
among other things.
The chassis design covers many features. Few of which are obvious based on simple dimmensions such as the lenght of the gearbox, ie distance from wheel centers to engine and also how much of the safety cell hangs over the front wheel center line.
keep in mind the regulations are defined on wheel center lines. This defines the car so careful attention needs to be placed in locating certain parts relative to the wheels, as this has an effect on air flow efficiency.
Hanging say 100m of tub over front wheel center line for example versus hanging only 50mm, would mean the tub that is further back from the wheels would have less disturbed air in the splitter area.
The black line is the front wheel center line. Tubs are located at different distances. Note splitter lengths.
Also if the tub is slim enough the car can have a huge splitter area. Splitter area is not defined by the regulations. If the seat area of the tub is small enough, it would make way for increased splitter area.
The redbull has a noticeably large top splitter area, as the tub is placed as far back as they could afford from front wheels. This is more like optimizing placement more than anything, but it adds to to the total.
The tea tray top surface area is only limited by the distance from front wheel center. Less tub over front wheel center line the bigger a splitter can fit.
The is a balance however, the nose shape is define by the distance to center wheel too, as the nose has to fitted to the end of the tub. It length and effectively it's shape is affected.
more thoughts to come.