Just a suggestion, I'm not sure if this is possible right in the WP interface, but it would be absolutely awesome if you could collapse and expand the parent/child trees in this plugin. The reason is simple- the destination of the page you need to reorder may not be close enough to see on the same pages view. You can adjust the number of pages shown in Screen Options to 100 or whatever so you can see both the page to reorder and the destination, but this is a clumsy workaround.
I've not yet figured out why WP doesn't support the typical expand/collapse functionality of a treeview yet, perhaps it's just that nobody with the appropriate skills has found the current display enough of a problem to change it. But I can tell you, it's a huge plus when you're working with hundreds of pages (as I am right now).
Just wanted to put that out there, thanks for making this effort!