We've made some further improvements to the zoom speed when scrolling using a mouse, particularly for Windows users. To account for possible differences in input devices and OS settings we've also added a 'Zoom Sensitivity' slider to adjust the speed, found under Options > Controls > Mouse.
We've also added a couple of new alternative keyboard shortcuts to go with the WASD used for panning, you can now also use QE for rotating and RF for zoom in / out.
Thank you for your feedback everyone!