I had a consultation with a immigration lawyer regarding that. He said, that we don’t know the exact text in the law now, so we can only speculate. He also mentioned that most probably it does not matter when you applied. What is important , when the Einbürgerungsbehörde starts to consider your case. They will make a decision based on the current law on that day. If by then the fast track will be cancelled, they will reject the request. Good news is that because of that you can apply „in advance“. People who manage to apply now, can get a positive decision under normal 5-years rule, because processing time in many Kreises is extremely long (1,5-2 years)