I really don't get the logic of this migration attraction debuff?
Oh wow this city has too much infrastructure! There are literally empty markets/workshops/whatever ready for me to move in and start working. This is so bad I'd better move elsewhere.
It also makes pre-upgrading stuff a chore. Instead of just building and waiting for pops to grow, I now need to constantly watch if I can build in that location or if building too much will make my pops go away. So what is the use of mass build???