Thief %/s (KMS Unlimited and GMS Tempest)

What difference does it make now that every class has weapon potential on their off hand?

Most of us don't have that yet. Eventually we'll get it, but for now, only the newer/dual-wielding classes will hold that advantage.

Pretty much this, not to mention not only can their off-hand get the 30% boss damage (or whatever the heck it goes up to now) but it's also very silly being able to get roughly a 40 weapon attack advantage over Shadowers on top of whatever else they have. At least now I understand the damage tables better.