Back late in the 4.x cycle, the kwin sound events were removed, I read the justification being that it was causing multiple dbus signals to be sent, causing a power usage penalty. However, with KDE 5, it appears that the knotify4 process is gone, and I am able to suspend the kded5 process, and other knotify sounds still play, and I might be wrong, but it appears there's not as much IPC required now for knotify. (although I might be wrong) Can the events be brought back?
No the ipc is still required. But one can use KWin scripts to emulate the behavior.