By my European standards that is definitely an SUV for me. It is less about ability to see a pedestrian than it is about the ability to kill if someone gets hit with a high vehicle front.
It is also about taking up a lot of space. European streets are small an parking spots are also small. These big cars frequently take up more than 1 parking spot.
I think it is a given that you can create scenarios for every law that make the law look stupid.
I doubt that the amount of 9 seater cars with enough people inside is actually significant to recalculate the law.
The decision by weight is most likely done as this is a value which can be easily evaluated.