Trolls?
Honestly, by the time you've killed all of the bosses and you've kitted yourself out in the best gear, you'll find that Trolls are no danger to you at all. By that point they're just a minor annoyance and as easily dispatched as a Greydwarf.
Calling it quits at Trolls after 2 bosses is a little lame. Still, if that's the way you feel, I wish you better success in your other games ;)