The trollkin also provide a nice medium base wall to hide skarre behind, and while tough really cant be relied upon, it can really ruin the day of someone needing to kill a certain model to take a zone or clear a path, it adds to the uncertainty and makes them devote additional resources they normally wouldn't have to. Aikos is good, and under the feat turn can actually kill stuff. Normally I use him as a threat extender and focus battery, but Skarre can actually make him a threat to important pieces.
I had the chance to play with my 15 point list vs a Legion player. I pulled off the win, but I'm not sure it counts, since she made some pretty questionable strategic choices and was playing a unit for the first time. 8" range is not great. They're outranged by virtually everything. That said, I was able to feat on them after casting Dark Guidance and got 4 POW 17 attacks plus fire AOEs. That was really nice and things were dead.
For 30 points I think it would be good to add Jussika to the unit and add Gerlak (take him free), then you still have points for Aiakos and the Shrike if you want, though I don't think it will be the best use of those 10 points.