ACT Section Retake
The ACT will get two changes starting September 2020:
1. You'll be able to take the test online (like students in countries outside of the US are required to), but online testing won't be required in the US. This doesn't really change anything.
2. You'll be able to retake individual sections of the ACT (English, Math, Reading, Science and/or the essay), rather than having to take the entire ACT again.
Unless the test becomes harder in the future, this will mean higher score superscores will become significantly more common. On one hand, this will reduce the value of a superscored high score (though it probably won't change the value of a single testing high score). On the other hand, this means that students will benefit even more from test preparation, as they'll be able to focus on one section when retaking.
As for colleges' superscoring policies, colleges currently have (and in the future will continue to have) access to both the superscore as well as each of the individual test scores students send. It's hard to fully know colleges' policies even now, so there's no way to predict how they'll look at superscoring in the future.
Overall this introduces some uncertainty about the future, but not enough to change the equation when deciding whether a student should take the SAT or the ACT. For now it's probably best to just keep preparing as usual. It was a pretty surprising change for me to read about at first, but now I don't think it matters too much. The College Board also does many things with the SAT that introduce uncertainty all the time. Maybe my opinion will change in the future.