I would say it would be much better to prioritize players before summons, but I'd still like it to work on summons.
So, after some experimentation with the Twilight, I'd have to agree that it's worth using for Single-target parses, equal or slightly better to wearing a toggle. Color me surprised. I still wouldn't use as a pure DPS when likely to encounter AoE, as it only shoots one thing at a time. One situation I *can* imagine it being useful in is mixed groups/ pickup runs, where having our class's Breath of Life answer available might save distracted healers some stress.
As on Live, I would not recommend having the Matriarch attack things while in a true healer spec; it tends to grab aggro from trash and get itself killed/ hold things away from the group while you aren't looking.
But hey, you can pull 40k+ in a pure summoner spec next update! 3/3 Pet builds are a go!
And so, Sorcerers taking up 4 SPC charges are a go. No bueno!