Switched from KUbuntu 16.10 with 5.7.5 to KDE Neon 5.8.2, and I love the fact the meta key now brings up the app launcher without needing a workaround (in addition to a bunch of other fixes -- awesome work!)

However, its behavior is inconsistent.  Pressing Alt+F1 will show/hide the launcher.  Pressing Meta will show, but subsequent presses will not hide the launcher (have to press Esc or mouse focus elsewhere to hide the launcher).

Also, in VirtualBox VMs, Meta+{key} sequences are properly captured and do not trigger host shortcuts.  But a single press of the meta key causes the app launcher to show, even when the keyboard is captured by the VM.