I wonder why I can not zoom and pan with the normal Mac OS shortcuts?
cmd + [+] = Zoom in
cmd + [-] = Zoom out
cmd +  = Reset zoom
and I wonder why the Mac OS Trackpad (2 finger pan and 2 finger zoom) don’t work.
Are there special Mac OS shortcut preference files for download? And is it planed to add simple trackpad features?
Please see the pink panel at the top of the page and give us that information.
If you prefer to use browser-like keyboard shortcuts for zooming, you can set these in Keyboard Preferences.
Audacity is a cross-platform app, not specifically a Mac app. We are limited by the features of the wxMac interface toolkit that we use.
You can use modifiers instead of two fingers on the Track pad. Please see the text at the bottom of Mouse Preferences.
It is possible Audacity 2.1.2-alpha (which is close to release as Audacity 2.1.2) may support horizontal scrolling without SHIFT. If you would like to, please try it and let us know. Grab the latest build at the top of http://www.audacity.homerow.net/index.php?dir=wx3/&sort=date&order=desc.