That seems like a nice feature. I'd go to the Canon forum and suggest it.
I finally just got a big enough card to hold twice the expected shooting volume, and the same sized card for backup. That way I don't have to worry, and I always have a backup copy if there is a failure.
Since I do not use the high speed shooting very often, its not a big deal If the SD card is slow. If I were going to do video, I'd do a low level format on the SD card first though.
Do they actually listen to customer request there? Yeah, switching to 64 GB cards would probably help avoid this as well. I guess I just hate having everything on just one card. I guess with a camera with 2 slots though, that's where the backup slot comes in handy in case something did happen to your main card.
Suprisingly, they do! Some of the announced updates like the ability to autofocus at f/8 , and the fix for slow autofocus with AF assist lights came about thru user input.
They should be able to do it in firmware. However, it might show in the viewfinder or the top LCD, and just looking at either place lets you see shots remaining, so I suspect that's their logic.
Perhaps if the shots remaining number flashed on and off, that might catch a persons attention. A user could set the number remaining before it started flashing, as well as disable the feature if it bothered him.
Its just a question as to how important it is and how many users badly wanted it. That's where a post on the Canon forum allows others to speak up.