I thought they got better with it as the main scenario went along, the scions were generally of doing their thing and they call you in at last minute as the "nuclear option", but they still managed to get stuff done. The lead up to Leviathan and such had them seeming fairly competent from what I recall.
The lead up to Leviathan was when they were at their most competent, if you ask me. Since then though, they've mostly been hanging around the Rising Stones, and handing out quests from time to time.
I mean, I guess there was that business with the Sylph dopplegangers, but that's about all they've done since then. Keep in mind, the Leviathan quest was almost a year ago, that's a lot of time to sit un-used.