I'm a big fan of BTT since at least 2012. One of the many reasons I like it is that it regroups many functions under one single roof. I prefer having 1 application running in the background than 10 sucking on CPU cycles, if you know what I mean.
In that regard, it would be very nice if within the "normal mouse" section, we could use "button chords" as triggers (a chord is 2 or more buttons pressed simultaneously on the mouse). Right now, it's only possible to assign an action to a single mouse button, but it would be real nice if, for instance, we could set both the "back" side-button on the mouse + the middle mouse button to trigger "Show Desktop" (just a simple example; button chords would allow for so many more possibilities).
Right now, I need to have BBT and SteerMouse running together in the background to achieve this. To me, SteerMouse is to the "normal mouse" what BTT is to the keyboard, to make a rough comparison. Actually, the "chord" term I evoked above actually comes from SteerMouse.
I'd really like to have such functionality within BTT, so I could keep only the latter running in the background. Plus, it would help avoid priority conflicts for button presses (right now, SteerMouse takes precedence on BTT for mouse button presses).