Hey I have thought about global events / worker management.
You should be able to increase / decrease the income of the factory staff. Workers should earn XP (for each car they participate or the time they work on a station). They should be motivated if you build a special type of car (sports /SUV). More expierenced workers build cars faster and make good publicity for the company.
Also I thought about global events like in Big Pharma.
They could be more workers avaible so you can reduce the income or you can face a economy crisis and the sales will drop you need to get rid of some workers 
. Or just a flu outbreak where lots of workers can’t come to work and the production of various stations will be slower.
More events could be.
- New Government (wants for example electric cars or smaller ones)
- You have been hacked (Information was leaked bad for publicity / sales)
- Your car was nominated for car of the year
- Your car was nominated safest car of the year
I could think about some more but let me first now what you think of those events.