#1. The Ability you gain access to over the course of the plot
The worst part is that you can turn all your weapons into Tenebrium weapons.
#2. Invisibility is overpowered
A single point in Scoundrel is necessary to choose Walk in Shadows as your starting talent. Afer that you can just steel everything that is lying around, enter guarded zones (enter Sacred Stone to steal some T when you are < lvl 10) and make the stealth passages a joke.
#3. Trait dialogue blindness
I guess that depends on how much you want to roleplay.
#4. Lockpicking has 5 or bust syndrome
The ability is completely useless. There are close to no doors/containers that you can't just bash in or open with a key without any trouble.
You should still get it to level 5 (3+ items) for the second map because that way you get to lockpick the one important door in Silverglen:
There is a cellar door in the small chapel of this town. If you get down there you can find 2 Bloodstones that can be turned to Starstones by using them. Together with the 5 from the first map you have enough to unlock the two best rooms in the Homestead:
The Seller of Secrets who not only tells you the location of secrets for a price, but also allows you to buy attribute and ability points once every level.
The demon allows you to respec (and get rid of the points you have put into lockpicking) and trade unused talents for 10 ability points or 2 attribute points.
#5. Inventory management!
#6 There are close to no sidequests that have any long term influence on the game.
The only big exception is Bellegar, who you will meet multiple times during your journey.
