While this feature isn't by any means critical to me, the response seems a bit overly cautious w.r.t. change IMO.

From what I can tell the main reason this has been tagged "WONT FIX" in the past is that you don't want cc-mode to depend on prog-mode. That's a bit odd, isn't it?

What makes that particularly strange is how pretty much every single major-mode which derives from cc-mode probably will derive from prog-mode, so for the loading of any mode derived from cc-mode, such a change would probably lead to very few effective changes.