Just to clarify/nitpick: SCs need some way to keep their fatigue from growing. That can be 0 encumbrance, it can be more reinvig than their encumbrance, it can be a life drain effect.
The buffs/items depend greatly on what your enemy is like and what your task is. For killing large numbers of chaff, AoE is nice, but what's really important is some kind of damage shield - Chill/heat aura, Fire Shield, soul Vortex, even Fear to rout them. And make sure your expected targets are vulnerable. Eg. undead are usually immune to Fear/Cold/life drain.
If he's an SC killer on the other hand, forget the area effect and go for multiple damage attacks. And all the buffs that help against chaff are wasted.
You're right Tifone. I guess I just had my own Sniper class that I used in my head, and after awhile my own reasoning became some sort of law. But when I do these charts, I'll try to do 3 of them, for SC, melee Thug, and ranged sniper.
I love mistform on my thugs/sc's. Indeed H1 (for a bless), A2 (mistorm, mirror image) and E1 (stoneskin, ironskin) are all I ask for and make me very happy.