The thing is, holding alt while you resizing used to let you disable the snap to feature quickly and easily, and it was so intuitive. Now with the new update, it makes what you are resizing, get mirrored in the other direction (if you are trying to drag it down to make it longer, it makes the top go up the same amount). This is never useful. If you wanted the top to go up you would just drag that as well.
A very useful feature, got replaced with a useless one. Who thought this was a good idea?? Make the alt function like it was before and get rid of this mirroring nonsense.