Admittedly, if the installer could assess the user's setup and automatically extract the proper .exe and any other necessities (OpenAL for Windows users) based on hardware and OS then it would be grand but we don't have that ability, unfortunately. Playing "vanilla FreeSpace Open" isn't really any less complicated: the same steps and number of separate downloads are involved, minus Zathras but plus the mediaVPs, so it's arguably more difficult to get regular FS2 up and running than TBP!
I definitely agree a working OpenAL link on either the main TBP/Zathras download pages/threads would be helpful. I think the links are already referenced second hand in those threads (under
Inferno builds, part 3 of the Zathras installation instructions), but it wouldn't hurt to make it more accessible. Maybe even direct link to the executables and Launcher themselves and cut out the middleman thread altogether.
Still, even when not counting pre-3.4 releases, The Babylon Project is still the most downloaded mod/TC for FreeSpace 2 on record, despite the disparate download track. Not too bad, and credit to people like FUBAR and hip63 for making that possible.