1) I like the plain druid over the shapeshifter. There are some great leather armors, such as the shadow dragon armor, that can really help out the plain druid. To me, the shapeshifting ability isn't very useful. Against high level opponents, one would have to be a fool to engage them in combat as a werewolf.
2) I like the skald better. I never use pick pocket skills and can use potions to improve the skill when needed. Skald song is pretty cool.
3) I'm partial to assassins, but that wasn't really your question. It really depends on how you use your thief. If you like to backstab, the swashbuckler is out. If you don't backstab much, the swashbuckler kit is great. They're good in combat, though they can't compare to the straight thieves in skills, due to the number of points a true thief gets each level. Me, I like to backstab, and no one compares to an assassin there.
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