Why wouldn't you insert somewhere in programs estimated time until it finishes the current task?
I mean, you can insert that both in CCleaner, Defragler and Recuva. It's nothing complicated, and it can be useful... I think...
[opinion] Well they're notoriously incorrect and I think we'd see a fair amount of "it said I had 10 min left for 48 hours when I ran Wipe Free Space". As we see that with both percent complete (more accurate) and size to be removed/actually remove[opinion]