I really enjoyed this article as I didn't know about Gnome-do yet.
G-Do seems to be a GTK/Gnome version of Katapult. For me, Katapult was one of the two the most useful and beautiful novelties in KDE (the other being Yakuake).
However for one reason or another, Katapult was dropped and KDE4 brought us (a new) Krunner. Which lacks the simplicity and the beauty of Katapult: just display a huge icon of what you are about to run.
The "Katapult -> KRunner" transition represents, for me, many of the things that went wrong with KDE4: the new version is far worse than the previous.
- The new version is visually cluttered, while the older one was absolutely to the point.
- The new version has worse key binding defaults (alt-f2 against super-<space>)
- the new version is functionally worse: krunner won't always focus the one and only selection.
- the previous version, despite having a "k" in the name, actually had (i) a pronounceable name (ii) that referred to catapult, whereas something that reads "cruner" doesn't actually wins any hearts or minds. And yes name that makes some sense matters, specially when showing the system to non-technical users.
(Hum, sorry for the grumpiness about Krunner, but I still can't figure it out how they could change one interface for the other).