I would LOVE to see an option for moving lights to take a straight path opposed to an arc! I have a suggestion to solve the issue, however it would require curves to be applied and be variable based on "user tilt." I have an interactive graphing calculator function that would show such a curve based on what "Tilt" is set to. I have not tested this at all and I can't make a guarantee that it will even function properly in any way, and must also be adapted. Here is the interactive graph: www.desmos.com/calculator/kat9giv2do. I have found this suggested before, however it was in 2013. A current console that has this function is the Cognito console from Pathway, its function is demostrated here: www.youtube.com/watch?v=V7dsRM0s1EI. It would ultimately make the EOS family of console become even more powerful!
:EDIT: I updated the curve as the sine function variant had failed its test via a virtualization, a new one has been calculated and has tested better in the virtualization. I cannot guarantee that the "curve" will even function correctly if applied in some way to moving fixtures. Values used to generate the "curve" will also have to become variable as it is designed for a fixed-variable "fixture," (0 to 90 deg tilt, and -90 to 90 pan).