Regarding my questions, so far I have the following answers:
1/ Character with Gamepad:
Is possible but not working great (the code is somewhere else on the site or in the forums, it is working).
In order to have a better feeling when moving the character (who by default follows too strictly the way points), it is recommended to create a LOT of way points.
2/ Shader with text:
The code exists:
eShaderExcludeTextsAndCursor 2
But it seems that it doesn't work. I have not had confirmation but the other exclusion codes are working (exclude interface works like a charm)
So there has to be an issue in VS with the exclude text?
3/ 3D environment:
It should be possible to do something like a sky on a sphere, and a plane at the ground. As long as it remains very simple, it should work by using the 3d objects. I have to do more tests but the inventory scene of Nigec proves that it should be possible.
4/ Camera:
It is not possible to rotate the camera freely in the scenes (only possible to zoom and pan + vertical rotation in the characters outfits).
However we can rotate the 3d objects instead of the cameras, thus we can rotate the world according to our needs, so with different tricks it could be possible to reach an interesting result...
That is the answers I found so far. If you have other ideas/suggestions, please let me know. Others could be interested too to read this thread in the future.