You surely know that a silicon chip does not have intelligence to recognize a white dress or a black tux. The photographer knows, and should handle it, but the meter just sees a blob of light. I don't notice horizontal to vertical differences myself, unless the scene changes (which ambient might, when you rotate the view). I don't follow the thousands of scenes business, I see no evidence of it. But at best if it does work, bottom line is we don't know what it will do. I do see that Matrix does shift undesirably when there are stray bright areas towards the frame edge. All that is about ambient, not flash, but instead, I use Center Weighted metering, I can just about understand what will happen then.
My complaint with the system is the D lens distance interference with direct TTL BL flash. This probably gives trouble to event photographers. Good premise, except the zoom lenses obviously don't know distance, they get it wrong. There ought to be a menu to turn D lens distance off. For example, in that case, FV Lock often meters different than without it. And TTL different than TTL BL, etc. Sometimes drastically different.
But we can complain, or we can just learn to use it. The latter actually works better
But yes, there are some things to know, and reflective metering does require attention, being somewhat less than point&shoot. But which is just how it works, point&shoot is just a novice fantasy anyway.
At least for fixed situations, if you want real good flash metering, use an incident meter, which meters the light directly, independent of the scene, but from the subjects position.