Why are the wicked resurrected only to be destroyed and sent to the Lake of Fire? In Revelation 20 the resurrection of the wicked is detailed. They are then judged and thrown in the lake of fire.

5 But the rest of the dead lived not again until the thousand years were finished. This is the first resurrection. [The righteous only were raised to life first]
12 And I saw the dead, small and great, stand before God [the wicked are then raised for judgement]; and the books were opened: and another book was opened, which is the book of life: and the dead were judged out of those things which were written in the books, according to their works.
13 And the sea gave up the dead which were in it; and death and hell delivered up the dead which were in them: and they were judged every man according to their works. [all the dead wicked are found and raised for judgement]
14 And death and hell were cast into the lake of fire. This is the second death.
15 Anyone whose name was not found written in the book of life was thrown into the lake of fire. [then they die]

I personally take the Annihilationism perspective, where the wicked are completely annihilated after being judged; they will exist no more.
So from the other perspective, the traditional doctrine of Hell, how does it make sense that the wicked will be resurrected, only to be killed, then suffer eternal torment in Hell (Lake of Fire)? Less challengingly said, why are the wicked resurrected when it seems unnecessary?
I think the misunderstanding here is that the wicked are resurrected and then killed.  I'm not sure there's a Biblical backing for the idea that those who rejected Christ will again be separated from their bodies.  Their souls will be in bodies when they are cast into the lake of fire.  Therefore, the punishment is eternal, physical, punishment in the presence of God and the angels (Revelation 14:10). 

The underlying belief here is that the soul was never meant to live without a body, and so it will not, for all eternity, but the question is, will the body be glorified, or will it not be?  From Romans 8:30, we see that the foreknown Christian is predestined, justified, sanctified, and glorified. 


  And those whom he predestined he also called, and those whom he called
  he also justified, and those whom he justified he also glorified.


So a Christian is glorified, but a non-believer will not be. 

In 1 Corinthians 15:12-14, Paul specifically states that the dead are raised.  He doesn't say that only Christians are raised, but all are raised:


  Now if Christ is proclaimed as raised from the dead, how can some of
  you say that there is no resurrection of the dead? But if there is no
  resurrection of the dead, then not even Christ has been raised. And if
  Christ has not been raised, then our preaching is in vain and your
  faith is in vain.


Not only this, but Christ himself states that all people will be raised, in John 5:28-29:


  Do not marvel at this, for an hour is coming when all who are in the
  tombs will hear his voice and come out, those who have done good to
  the resurrection of life, and those who have done evil to the
  resurrection of judgment.


So it's not only Christians who are resurrected, but ALL people, though their resurrection may be followed immediately by very different experiences.  All will worship, but only those who are written in the Lamb's Book of Life will be justified in the eyes of God.  All others will bear their own sin. 

As for the underlying idea that annihilation might be preferable to eternal suffering, and eternal torment, I can only conjecture that the reason why eternal torment is taught instead of annihilation, is because annihilation is simply "not complete enough" of a penalty to pay for the sins that have been committed against an all-holy, perfect, just, and loving God.  The object of the transgression must be taken into consideration as well.  Whereas death may be a sufficient penalty here on earth when sins are committed against humans, it is not sufficient in eternity, when committed against an infinitely good God.

(As a side note, some of our discomfort with eternal torment in western culture comes from the western culture's over-emphasis on love and forgiveness at the expense of justice.  In Islamic cultures, they may find our emphasis on love and forgiveness somewhat offensive, preferring to value justice more highly.)