If you're going to do the roguey things like lockpicking yourself you don't need astarion because that's pretty much all he's good for to me these days. I like to bring Shadowheart, especially for act 2(I respec her light domain) and then Gale. If you'll be playing ranged, you could possibly bring Karlach instead.
I don't like Wyll, myself. I've never done an evil play through, and I've yet to get to the part where I can take Druid B or their fren.
