Red's hiiamboris has made an alternative console (built on his "Spaces" VID alternative). It appears you can go back to an earlier expression and edit it, and if you do, it will ripple the changes through running all your future expressions again.
It's called "Spaces Console", and it's an interesting idea. Sort of fuses together a watchlist with a console.
Note that Ren-C's Web Console can keep Ctrl-Z'ing to undo console output and go back to edit previous expressions... but you lose the subsequent commands. Though the web console also has a watchlist like the one in the Qt Ren Garden.
Anyway, something to think about.
Note that the current implementation appears to be slow (Gitter link):
Gregg: "I thought it didn't like
repeat i 100 [print i], but just took a long time to process it. ~10s."
Boris: "printing is O(n^2) atm, need to overcome laziness and make it lower level :D"