While Baras was efficient at what he does, he places his own advancement above the well being of the Empire. While not unusual for a Sith, it's that sort of thing that usually leads to the defeat of the various incarnations of the Sith. His, and Thanaton's idiocy cost the Empire Corellia if you ask me.
Actually it was Zash who was doing trying to self advance when she got Skotia killed, not Thanaton. Thanaton just did what he did to punish Zash and those who served under her (including SI).