I would support these points. I have a daily commute that ends when I turn into my street from a 70 km/h road. The turn is very step and drops about 3 metres over about 10 metres. The only way I can stop the Ray going red is if I have the luxury of not being tailgated by drivers in a hurry. Under these conditions I can drop the auto down a gear and engine break to the intersection and arrive at a much lower speed otherwise I constantly go red so as not inconvenience following drivers or risk accidents. I am often overtaken through this intersection which has double unbroken lines (which I appreciate is not Ray's fault).
Note that the reverse is true when leaving my street and having to accelerate quickly uphill to avoid being a problem for other drivers.
So having the ability to factor in angle of descent/ascent or change of elevation would be good but I appreciate that all depends on whether the phone in use has the functionality. Although I suspect all modern phones with BLE do have that capability.
Another issue is the length of very short maneuvers. Specifically if I reverse the car from the garage onto the driveway the fuel economy is very high for a distance of a few metres. Do these short maneuvers impact the overall score? They could skew the stats so I hope they are not really factored in, especially if the car is in reverse gear. Perhaps distances under a specified length of, say, 20 metres, between engine start and stop, are not included in the stats (although that might be hard to configure if a car has auto stop/start).