I know that this post is quite old, but since i'm playing the game on hardcore now,i thought i would chip in.
These three abilities Sneak
and Summoning dolls
are "game changing" to the point that they can trivialise the game.
Prioritise to always level Sneak as far as you can to the current maximum and when you enter combat always do so in sneak mode. Aggrevate the monsters one by one, until they all drop. If more come towards your side, then just walk away a few steps.
Using archery weapons with sneak is even more deadly, as you can fire 2-3 times move a few steps and repeat the process, without the monsters ever be able to hit you.I managed to kill all the level 6 ghosts at the early stages when i was level 4 with ease.
As for pickpocket, all i have to say is wow.
You need to teach and level it up with only one of your characters, doing otherwise will be redundant and i would recommend to level it up as much as possible.
If you play it clever, you can get a lot of high value items for free and even steal your money back.
Here is a tip: Save high value objects such as permanent potions or a rune that has a big value. Sell it to the vendor and get equal value items. Then pickpocket him and steal it back. Repeat the process until you got everything you wanted. This ensures you will be able to get anything you want from vendors and your money back... - I feel this is a bit cheating,so you may avoid using it if you want. You are limited to how many times you can steal based on your level,so save before doing so.
As far as summoning dolls go, Stabbey you say they are useless but I think they are game breaking.
Doll used as a mule:
First you can use them as an unlimited space mule, which means you can throw anything you want in it. The doll won't be able to move at all but that doesn't matter if you use it as a mule.
Doll used as a killing machine:
Each point put into summoning dolls->Upgrade->Level skill, gives your doll 2 extra level ups which also equal to 10 stat points.
Both your characters and even the doll itself can level up this skill and the available levels will sum up. What's more is that you can have multiple instances of a Summoning Doll Upgrade in your skillboxes, which means the same character could invest multiple times into summoning doll level upgrade.
For ex. i could have on my hero early on invest into Summoning Doll Upgrade Level 3,four times if i have 12 skillpoints.
In a test i did,at just level 8 and investing both of my character's skillpoints into summoning doll upgrade (12 each) and the 4 starting skillpoints the dolls gets,my skeleton doll was level 57 with a 2handed sword demolishing everything.
Just summon it whenever there is combat and everything dies.
I reloaded back my game after trying it,to play without this because it was just silly,but this shows that if someone wants to play a Doll-master,he certainly can. At this point however the doll will become the main protagonist
. Do note however that you cannot unlearn points spent into summoning doll upgrades