Just move Options to the left and add Templates (or "Preset...") to the right. Then have a menu like the RM&CF function.
Drag & Drop works anywhere in the Convert Format Action Window, so you don't really need the large area for Drag & Drop on the right. You could even enlarge that symbol and put it in the background for the whole Action Window, to indicate the whole window is active for Drag & Drop. You could make the "Convert" button smaller to make the symbol more visible. It doesn't need to be as big as it is.
Or if you don't like that, there is already an icon in the top left of the Convert Format Action Window, which shows a tooltip of "Tools" but doesn't actually do anything when clicked on. You could put template management behind that, much like the "Customise" function for the Tag Action Window. But that is a bit hidden away, and not obvious to users.
My preference though would be to add a Templates section to the top of the Options dialogue window, so that a template could be selected like a Zone is under "Options > Audio", and then add the ability to Save, Edit, Delete templates as required. Again, my preference would be to add a "Manage" button to the right of the template name, and have all the required functions under that, just like the Tag Action Window template management process. Please include the functions to Add, Edit, Save, and Delete a template, plus Save to file, Load from file, and perhaps even the "Copy Template To Clipboard" and "Add Template From Clipboard", or a "Create New Template from Current Template" function. But the Save to/Load from file functions could be used for that if you don't want to add the clipboard functions.
Note: If a template is loaded, and then some setting is changed once off, the OK button shouldn't save that change to the template. It should just use the changed setting for that one conversion. Hence the need for a Save function under the Manage menu mentioned above, which the Tag Action Window templates functionality doesn't require as all changes are saved. Maybe clicking the OK button without first saving any options changes should result in a popup asking if the user wants to save the changes to the template, to be consistent with other applications.
In fact, I always thought it was a bit strange that the "Details" and "Options" functions were accessed through links, while the "Convert" was a button. I guess there could be some logic around that, but why not just make them all buttons and move "Convert" to the bottom row where the "Details" and "Options" links are, and have three buttons in a row, with the template management under Options as above?
Thinking about the above, I have just mentioned three ways in which templates are managed in MC. No wonder users get confused and don't/can't find stuff. Please don't invent a fourth way.