Over on BMWBLOG, you'll find a highly detailed article on regenerative braking. The article explains this feature in depth and then discusses how various electric cars implement regenerative braking and one pedal driving. It's a thought-provking read, so do check it out here, but be warned, it's long.
Here's a snippet from the article:
Four-wheel versus two-wheel magnetic braking
Magnetic braking only works through the wheels connected to the motor. The i3 is rear-wheel drive, and therefore the magnetic braking is through the rear wheels only. Since the front wheels are the most effective at braking (due to weight shift on deceleration), the effectiveness of the i3’s magnetic braking could be better. The MINI E, with its front wheel drive, could support stronger magnetic braking, and did (but the RWD ActiveE also had magnetic braking levels higher than the i3). Both trial cars experienced some magnetic braking anomalies in certain conditions, however.
The all-wheel drive Tesla Model S 70D provides balanced magnetic braking (and more even tire wear). As implemented, its magnetic brakes are independently controlled front and rear; resistance is automatically adjusted at each axle to match conditions. It should be less prone than the i3 to traction loss during difficult braking conditions.
The 70D therefore has the potential to have stronger magnetic braking than either the i3 or the MINI E. But does it?