When people ask what's so great about designer desktop, one of the simple things I mention is the record count. I think this would be a great addition to designer cloud. As an example, here's a pointless workflow in designer cloud:
Seems ok, but here's the same thing in desktop:

By just looking at the picture, you can see that I messed up my join and my 780 records have ballooned to 608,400. I can also see that I didn't have any unjoined records pretty easily. Designer cloud has this record count information when you click on each tool, but I think they should display the counts on the canvas like desktop.