User blog comment:James12708/Yahg in multiplayer?/@comment-4967682-20120506215130/@comment-4967682-20120513002745

"Its multiplayer its not like theres a real story connection letting us play around with other races outside our boring ones we got would be very fun"

Actually, there is a story connection. It boosts galactic readiness and you can promote classes to give yourself a commando team in single player. This commando team becomes a powerful war asset (+75). If the yahg were added, then they'd have to be part of those squads, which makes no sense at all.