I find the dragging way for reordering pages in the editor very annoying and unergonomic, as well. More often than not you miss the position of the object you are moving and it seems that you cannot move the bottom object one position up. It would be much easier to click on the object you want to move and then have up and down arrow buttons to position it properly.
You can drag and drop pages both from and to last position. Can you let us know (or maybe record with Quickcast or Licecap) the issue?
Oh I see, I witnessed this, folders are hard to move in between other folders. Probably because they wait for a possible “add in” interaction.
Anyway i’m sure this can be fixed. A long time ago the moving system in the Navigator tab was hard to use, and Webflow team fixed it and now it’s really behaving great.
IMHO we can skip the arrows and this behavior can be fine tuned 
What is wrong with the arrow buttons? They are much more ergonomic, you do not need to hold the mouse button and scroll at the same time. I hate it when I need to “target and hit” something with the mouse.