Re the "reorder" button, there are some usability issues with removing it and just letting users drag the pages in the same way they would if dragging files around using windows explorer as proposed,
This was the first approach we took to moving pages and what we found is many people who were not particularly confident with their mouse, inadvertently moved pages around when trying to do other things such as open pages.
I do however think the current reorder functionality can be improved significantly. Some ways I think we can do this;
1) Currently pages are moved on the draft site as soon as you have moved them in the CMS. I think it would be better if you needed to "confirm" the move after you have moved them, in the same way you need to use the confirm that the pages you have selected in delete", are in fact to be deleted by clicking on the "delete selected pages" button. To do this we could introduce a "confirm move" button.
2) Supplementing this, we could then have a "undo move" button, to undo the changes.
3) Another usability enchantment here would be when you move the page, you would be promoted "would you like to change the location of these pages on the live site as well as the draft site". I find it annoying that after you have moved all the pages, you need to go through the site and and click on all the pages you have moved, and seperattly publish them. This is partially difficult when you can't remember which pages you moved, as currently there is no way to compare the position of pages in the draft and live sites.
We would need to be careful here that this publish operation only "publishes" the change of location to the live site - excluding any other changes which may be sitting in the draft site for the affected pages.
4) We can make things easier, for people moving pages by increasing the space (padding) between all the nodes when in drag mode. I've noticed several people (myself included...) struggle to move pages up or down as it's hard to put pages in the right "drop zone" (currently the drop zone is about 2-3 pixels which is too small for many people). By increasing the padding, we can make the drop zones much larger, which will make moving pages much easier.