The Monster Hunter: World mouse and keyboard controls were not quite perfect when the game released last month, but a new update promises to smooth things out a bit by adding new mouse control options for the in-game camera. The new control scheme, which Capcom said "is in line with the control standards for most PC games," can be accessed from the Controls tab of the Options menu.
The update also changes the location for the "Relish the Moment" event quest to Elder's Recess, "to improve playability." The quest itself remains unchanged, however.
To ensure you have the latest update, check the version number in the top-left corner of the screen when you launch the game in windowed. (I don't know why it has to be windowed mode, but that's what the update says.) Revision 153524 is, for the moment, the one you want to ensure you're up to date.