Howabout a box somewhere that shows the positions in a given sequence.
The positions would be labeled 1, 2, 3, 4...
The user would be able to drag and drop position 2 above position 1.
And they'd be able to delete, cut, copy these positions onto the clipboard and then paste them in the same or a different sequence box.
This way, you won't need buttons like 'Insert', 'Delete', 'Move Above', etc.
That way, people get to stick with the hotkeys that they're familiar with, instead of having to learn an array of new buttons.
I find that it's the simple interfaces like that which keep me coming back and using the program again and again.
It doesn't really matter how much functionallity something has if it's not intuitive.