I'll just repeat here what I wrote in another thread on the same topic. Since the game is fully 3D with an awesome world you can see in the distance - the way it tilts down when you zoom close to the character kinda shows this off - there can be NO valid reason not to allow the player full control over vertical angle. So what if it means a lot of jittering due to collisions in some places - it is up to the player to manage his camera in that case. It works in pretty much all other games, it would work in BG3.
I kinda suspect the restrictive camera is an inheritance from the old 2D predecessors, but it is stupid nonetheless. Anyone else remember when Neverwinter Nights was released and everyone complained about the camera, a mod came along giving free camera, and some time later the game had free camera as vanilla? I'm hoping the same thing happens here.