This request is being tracked already:
Issue 1720 – Persistent transfer queue
You can vote for it there.

I am trying to switch over to WinSCP from FileZilla but I have one feature which is not supported. In FileZilla I can open a collection of files, edit them, save them and have them uploaded. I don't believe this is supported in WinSCP. Is there a way to script this or is this something that could be added?
Let me make the case for this workflow over the synchronize directories option:

• Browsing servers with million of files in thousands of directories makes synchronize take quite a while to sync.
  
• Editing files in several paths means a manual upload of each file requires changing directories and uploading each one. Which very nested directories this can be time consuming.