Knossos is generally preferred now, as far as playing FSO goes it should be feature complete now. Just note that it'll redownload all the mods (in case you're on limited download internet). And I haven't run Arch so I'm not precisely sure what dependencies it needs.
Just in case you continue with wxLauncher, as Linux has case-sensitive filesystems by default your mediavps 2014 folder name is going to cause issues as well (as most, but not necessarily all mod.ini files use the lowercase naming for mods). Therefore I'd recommend creating a softlink like so (in a terminal):
cd freespace_2
ln -s Mediavps_2014 mediavps_2014
And lastly, the FSO game engine doesn't create mod.ini file, modders create them & players install them.