I like how Directory Opus is queuing up successive file operations. Unfortunately, the automatic checks will only catch a subset of the cases where two operations need to be done successively rather than in parallel.
What I think would be great is to be able to queue any file operation manually (like, by holding down a certain key). So, say you are deleting the contents of a directory and then you want to paste some files into the empty directory but you first need to wait for the deletion to finish as some new files conflict with old ones. Right now, you need to manually monitor the operation and then issue the copy or otherwise you will have the copy and the delete stomping over each other. If, however, you could manually queue operations such that they would wait for the preceding operations to finish, you could simply issue the copy right away and Directory Opus would do the scheduling for you.
NB: Directory Opus is hands down the best file manager I've ever come across. Love the software.