A « horrific » -1200 ? That's one woodelf residence, 12 squares. Elvenar has problems (namely, premium culture buildings far too expensive in the latter chapters, if you're reading Marindor), but this update isn't one of them. I've looked at your city in elvenarchitect, it is quite clear you have WAY too much space devoted to factories, workshops and roads. Delete some, end of thread. My condolences if you're playing for ranking, but what is the point of that anyway ?
The player you are responding to has lost 1900 population from this hastily implemented update, and he/she is on the lower end of the losses I have heard of. Maybe you think that's a minor amount, it does however represent a time and resource investment, when perhaps the player had carefully planned his/her way through the S&D chapter. It's a setback, a major one perhaps to a person's experience.
This update shows exactly what is wrong with Inno and their horrendous communication skills, costing a lot of people literally thousands in population, announcing such an impactful update a day and half before the hammer came down.
This will cost Inno players, and goodwill, dropping people's willingness to spend money. Coincidentally, income is what keeps a game like this afloat, so it's generally a bad idea to wreck your customer's cities / plans in such a way.
And mind you; this is not the first time Inno just changed things around with barely a warning. It stacks up.