MichelPM, yes I did.
Just before Apple admitted the CPU throttling and following the findings presented in this same thread, I ordered a new battery from ifixit and changed it myself (there is an old post around here where I explain this). Also I checked with CPU Dasher that my CPU went back to 1400MHz.
To sum up: The phone is performing much, MUCH, better, it is now usable, but usable is not what I expected from a 1000€ phone.
Besides a general clunkiness that is clearly noticeable in every aspect, and that was not there with iOS 10, which was butter smooth, I'm still experiencing the following issues:
-The keyboard is still suffering from mini freezes randomly, albeit it performs far better than it did before the battery replacement.
-Siri sometimes takes 10 to 15 seconds to start listening when long pressing the main button, even more when saying 'Hey Siri'. And many times she starts thinking for a while (after receiving whichever order I gave) and eventually just does nothing and closes.
-Fast forwarding (or rewinding) music or podcasts sometimes (many times) does the opposite thing.
-Many emails just don't load when trying to read them, I have to close the mail app and open it again.
-Sometimes the camera app takes ~10 seconds to open, others just 2 or 3. Taking pictures is also laggy.
-Youtube suffers from ~10 second freezes when receiving user input or when ending a video, and sometimes does not orient the screen properly (this could be youtube's problem, but it worked fine on iOS 10).
Maybe you are right and it all gets better when they let us opt out, maybe all those micro stutters is the throttling jumping in for a micro second, maybe ifixit batteries are just not as good as apple's, we will see.
In any case, I STRONGLY recommend to have your batteries replaced, the performance improvement is huge.