Angular 1 still has an great community and is getting updated all the time. A lot of documentation is available for it, it's also very mature and it's still one of the best tools for the job.

Developpment is constantly adjusting/renewing, even though this time we know that in a year are so we have to learn something new... It happens all the time, so i wouldn't make a big deal of it.

What if you chose React based on your current opinion and next year React version 2.0 (or whatever) changes the entire core...

Just choose the right tools for the job. Angular 1 will still be getting support and bugfixes next to Angular 2.