I'm having the same issue with my new laptop. 2-finger scrolling through items in build/buy mode and CAS (I didn't get much further in the game to see if other scrolling things were affected) is super choppy and either scrolls too much or not at all. Occasionally I can get single lines but it seems really random. Zooming in and out is fine. Connecting a mouse does seem to be a fix but it's just not how I'd prefer to play.
Not sure if there's some sort of compatibility issue with the game and the specific touchpad in my laptop, but I'm not having any issues using my touchpad to scroll on any other game/program other than TS4. I've tried every troubleshooting thing I can think of - adjusting my laptop's touchpad settings, turning off smooth scrolling, updating and reinstalling my touchpad's drivers, repairing my game, uninstalling and reinstalling Origin and TS4. I even did a clean install of Windows 10, and nothing seems to fix it. Really hoping someone has figured it out :/