ok, to clarify a few points made my chris:
the installer installs all files, every single one. The problem you face is, what i have mentioned above, the "MSACM.vorbis=vorbis.acm" in the system.ini, it is just kind of a "wrong driver/lib being used" problem, with the "MSACM.vorbis=vorbis.acm" in the system.ini, the sounds all play just fine and the channels aren't displayed "red" anymore.
To the wineasio violates gpl: not true.
wineasio is gpl, and requires the asio.h header file from the asiosdk, which is under a dont distribute license, but can be freely downloaded from the steinberg homepage.
wineasio is being distributed without the asio.h from steinberg, you have to get it yourself, then compile the wineasio.dll.so. The only violation would be distributing the asio.h with wineasio, and it wouldnt violate the gpl, it would violate steinbergs license. On the opposite would be a compiled binary, that would violate the gpl as you cannot distribute the asio.h to accompany the binary. I think the wineasio devs already have a gpl compliant replacement for wineasio in the newer version 0.9.0, BUT that version doesn't work with fl if i recall correctly, but i think it can be used to compile the awesomely working 0.8.1 as well.
So it would be legaly possible to get wineasio source, get asio.h from steinberg, compile, regsvr32 it.
done. works.
wineasio doesnt work on macosx: also, not true.
jack is available for osx, namely jackosx http://www.jackosx.com/
wineasio only requires jack, and wineasio recently merged with a project called WASIO, which was, wineasio for osx, and now wineasio also is macosx compatible.
VST:
those vst are all third party, so i doesnt count towards fl studio. All fl studio plugins copy protection are the same as the copyprotection of flstudio itself, a reg file. works.
hope this clears some things up.
in my opinion, one of the biggest problems would be gdi+, as most of fl studios interface is being drawn with gdi+, and gdi+ is very slow compared to native. Apart from that, audio computation etc, is working almost on par with windows. Latency issues are being fixed by wineasio.
EDIT: i checked winasio again, and it is under Lgpl so, distributing a compiled binary, without giving out the asio.h source is legal.
EDIT2: another problem is underlying windows which dont show up on the window managers list (taskbar, whatever), some notifaction windows for example, if you lose focus on those, its hard to get back. and fl studio locks its interface when notifications/warnings are being shown.