I also absolutely agree with this. Being able to tie multiple io24 manipulations and toggles to a single StreamDeck button would be fantastic.
I suppose ProSonus believes the tablet control is sufficient. It can be for some cases. But I really need that one touch action.
Regarding mic mute (or should I say Stream mix mute), I can recommend the Audio Mute plugin available for the StreamDeck. You can set it to toggle mute whatever your default recording device is or a specific recording device. The mute is done at the OS-level, basically it's equivalent to toggling the mute button in the Windows Audio Devices screen. The plugin also detects the mute state so whether you mute within Windows or via your StreamDeck, the toggle status is always in-sync.
Another useful plugin by the same author is Audio Switcher which allows you to switch your default audio device (works for both input and output) with a push of a button. Really nice if you to swap between different Stream Mixes, although results vary depending on the recording software or broadcast software and how they handle the "default devices".