Okay this is the last one, I swear!
I figured it out!
Although somewhat hacky, I added a listener to ionSlideDrag, which calls the rotate function to recalculate the slides’ data and recenters it.
Of course I also don’t want to call rotate with every ionSlideDrag, that would be way too much. This is why I also added (mousedown) to the ion-slides parent component, which toggles a boolean value. This ensures, that for each drag sequence, rotate is only called once.
Here is the updated plunkr:
Look how smooth swiping is now!