On top of what was said above, there are some skills that are useless:
- thief skills like lockpicking or sneaking ar either of limited or no use or can be substituted by spells. Making a mage character instead of a thief character gives you the thief benefitz and you can cast spells on top of that.
- I found repairing to be useless as well, usually you'll find enough equipment in the dungeons and there is a mountainman smith who will repair equipment for gold.
- Pick only one weapon and use that, don't try investing in more weapons skills. It's better to be good with just swords than passable with swords, axes, maces slings and bows at the same time.
- Track, traps and charsima are useless as well.
- apprais can gie you better prices when bartering, but I didn't have any problems without. Plus, you are stuck in a dungeon, so all you gold is useless if no one wants to trade it.
. Swimming might seem like a handy skill, but I found it better to just avoid water altogether. Put a few points into it if you want to.
That said, Underworld is not a very hard game, so you can make a flawed character and still have fun. I rolled a paladin on my first playthrough and i didn't put many points in strength, forcing me to think very carefully what i would carry with me due to the weight limit. In a way playing a flawed character can ake the game more interesting. just roll a decent character, avoid useless skills and see how it plays out.