Thanks for reporting this 
We’ll take a look, all of these are not related to a particular update (adding features to the editor is not magically making the rest slower ;)) but more the conception of the events sheet that has always been a bit brittle for large sheets (which we try to avoid by encouraging usage of behaviors/custom objects, but it’s right that it does happen to have very large events sheets anyway).
For sprites, it’s strange to see such a long time, we’ll also have a look.