Here is some tweaking you can do if your mouse sensitivity is still to high after tweaking it in-game.
Windows + R -> run "shell:local appdata\SWTOR\swtor\settings" -> Open YourAccountName_Account.ini in Notepad -> Add "Controls_CameraRotationSpeed = 0.01" to the last line.
Of cause depending on your DPI settings and resolutions etc. you'll need to modify the setting, just make sure you save before you exit Notepad and restart the game for the new setting to take effect.
