It would be awesome to have the mouse control option back as it existed under Prepar3d.
We had exactly the same interface in FSX ( some key are not exactly the same, but they are very similar ) and no FSX user felt it was too complicated.
P3D was an exception, because there's a specific Camera/Mouse API that works over the actual 3D scenery that is exclusive to P3D (not even in all version, it requires 4.4+), which we used as soon it became available, so we surely plan to do that in MSFS, if it will eventually come.
Lots of developers have asked for a Camera API in MSFS, but there's no knowing IF it will ever be made, and if it will also include Mouse support.