and then force a fixed view camera, eliminating most of the advantages of 3D in the first place.
Fixed-camera view means designers only have to design for exactly one camera view and know exactly where the camera will be placed. I don't see any advantage to being able to rotate a camera in bird's eye view games, it's just annoying.
You could've had gorgeous 2D art and painted backgrounds.
Most "gorgeous 2D art and painted background" games you can think of used prerendered assets which were sometimes handpainted over -- mostly due to technical limitations.
The downside? It's not a real 3D world. No real-time lighting or shadows, in general no environment interactions, physics issues, etc.,
PoE used extensive hacks to get around these limitations. Even Sawyer has admitted it was too much effort to be worth it.
PoE(deadfire, at least -- first PoE probably used a similar but simpler system) is just a pre-rendered 2D background draped over a real 3D world. It was easily the most extensive "2D pretending to be 3D" system in any cRPG, and possibly the last time it will ever be used by a big budget game.
To fully understand what I mean, watch this video to the end:
You'll even see that the interactable objects are actually real 3D objects and not prerendered. They stick out ingame like those old cartoons where the animated things would be of a different color.
Collision meshes are invisible, but I wish they would have toggled them on to give a better idea of what's going on here. PoE is a
real 3D world with a semi-2D presentation.
They used various rendering tricks to enable things like real-time lighting and shadows(entire scene has one giant normal map baked for it.) And, IIRC, static objects don't cast dynamic shadows -- only dynamic objects can.
All this just to claw back the things they lost by not actually being 3D.