Haven't played Trespasser yet, but so far these Sigils are sounding like Fade-Touched 'Berserk' trait. Seriously: Deal +10/20/30% damage, and take +100/200/300% damage? Who looks at that and thinks that's a great idea? You'd have to micromanage your stealth rogue all the time, because as soon as they brush against an dog or an AoE, they're gone. (And that's not even accounting for enemy rogues/stalkers.)
If they're supposed to be the equivalent of runes, I would see '+10% fire damage' on its own to be reasonable. Let alone adding "also everything else sucks' on it, too.
A staff has by end-game, about 80 dph. A superb spirit rune is 32 dph. That spirit damage is MORE THAN A THIRD of the base dps. Certainly not just another 8. It's on every basic attack, too, instead of 'only if you do this one element'.
Seriously, sounds like sigils need to step up their game.