Justinia's Favour as an honorable mention, being the only gloves granting +1 bartering
Especially as you can go and get them immediately on landing if you know where they are.
Gareth's dads dagger for the thieving point is good too. Is that the only +1 thievery weapon? I think so.
There are a few good things dotted around (lots in Arx) - it is just if using them routinely (rather than for specific tasks) they become useless compared to vendor wares once you are past their level.
I think it's indeed the only thievery weapon. So getting thievery to 10 is only possible with the dagger, Papa Trash's unique armor, Gloves of Acquisition and a thievery belt. Or to get thievery to 5 with any character.
Given the inability to upgrade items uniques will lose their charm after you level up apart from the above mentioned few utility items and of course Shadow's Eye.
I didn't mind having to invest points into crafting in D:OS1, because it meant creating awesome stuff without having to worry about rebuying items every level. I really miss this in D:OS2.