I'm expecting "tada" "bombshells" to be confined nearly exclusively towards features that enhance the Unity desktop on initial reveal. I can imagine some feature reveals of this nature causing headaches for the Ubuntu community trying to field a GNOME remix, if Canonical needs to further modify the GNOME stack to deliver something new like a tweak of the gnome control center (if Unity hasn't reimplemented their own CC yet), but I wouldn't expect that sort of thing to show up late as big reveal. I fully expect these things to be very tailored to Unity initially and positioned as desirable unique features that differentiate Unity from other options.
Users of KDE as implemented in Kubuntu should probably be pretty safe from any blowback from a late breaking Unity desktop feature.