Do weapons have hidden multiplier or some just plain bad?

Well yeah, Vanquisher is one of rare weapons that doesn't shoot wet noodles.

Vanquisher has 286 damage on SP, while it got a whooping 680 on multiplayer...On the other hand, weapon like Avenger, or even P.A.W barely has any damage buff at all. Nice job at balancing over there BW.

I heard the Vanquisher has a better headshot multiplier than every other sniper rifle. Don't quote me on that, though.

Vanquisher seems like the only sniper rifle people use at the moment in Silver/Gold, being an infiltrator or not. Is it really that good?

I got carried on gold by some dude with a Vanquisher I. Watching in spectator mode, I'll have to say it's the best weapon I've seen.

If they're anything like in ME3, then Widow and Black Widow will have innate penetration, so that's something.

I unlocked the widow and im loving it

They are just plain bad. I want to think that this has something to do with how gear is different in MEA, what with Jugg shield turning you into The Juggernaut (of bitch fame), so maybe Combatives and Guerrilla upgrades will make more guns, uh, not shit.

If that's the case though, making gun and build viability so heavily dependent on equipped gear is as bone-headed a design decision as it gets, but it's still a better prospect than guns permanently being just something you need to slap a melee optimiser on. We'll know soon enough, after one or two store rotations and balance patches.