No one believes Sauron is around and the missions she has been going on have been to humor her, it could be possible the team are just a token force thrown together. I don't remember if they dropped a date, but Sauron re-emergence occurs something like 600 years after the defeat of Melkor.
I believe you are greatly underestimating legolas, he's son of the King, he was exceptional among his elves. Big rule with Tolkien tends to be your ability is tied to your status. Legolas, son of king; Gimli, descended from Durin; Aragon, King etc...
The only other troll we see fight in enclosed spaces is in LotR and it was fighting beings that are significantly stronger than the average elf.