I’d love to see VST(i) support in the OSX release. There are few plugs, which are just released as VST(i) for mac, and not as AU(i).
And maybe its possible to set individual paths for plugins? 
From the manual page: http://www.manual.ardour.org/working-with-plugins/getting-plugins/
LADSPA plugins are shared library files. They need to be installed in either /usr/lib/ladspa, /usr/local/lib/ladspa or in a directory mentioned in your LADSPA_PATH environment variable.
LV2 plugins are folders/directories. They need to installed in either /usr/lib/lv2, /usr/local/lib/lv2 or a directory mentioned in your LV2_PATH environment variable.
Linux VST (LXVST) plugins are distributed as shared library files. They are typically installed in /usr/lib/lxvst, /usr/local/lib/lxvst or a directory mentioned in your LXVST_PATH environment variable.
We will we be adding a way to set these search paths from inside the program, because of the difficulty so many OS X and Windows users have with setting environment variables on their platforms.
There are no plans to add VST support on OS X. The VST specification does not cover Cocoa plugin GUIs, and since Carbon was officially deprecated 14 years ago and actually started to be removed from OS X several years ago, this is a problem. Cockos (Reaper) defined their own “extensions” to the VST spec to cover this, and VST 4.x (not yet “released”) also defines enough stuff to be useful. But an official VST compliant plugin at this time, using either VST 2.x or 3.x, cannot have a Cocoa GUI. We are not going to jump backwards through hoops to support this.
There are at least a couple of excellent VST->AU wrapper plugins out there: for people who really love a VST that is not available as an AU, I’d recommend their use (which is what says when people ask about VST support in Logic).
Thanks for explanation.