The main problem I see with your perspective is that you are evaluating the expression "eternal punishment" from a modern English perspective, not from an ancient Hebrew or Greek mind. Much study has gone into their fancy way of writing. Keep in mind that the word "eternal" or "forever" is translated in the LXX from the Hebrew word "eternal" or "forever" in context of numerous occasions in which the subject in question came to an end. Such as Samuel as High Priest forever, or Jonah in the Belly of the Whale forever.
Keep also in mind that there is no such expression as "eternal hell-fire". Or even "eternal hell". Remember, we already know that souls "die" (Ezekiel 18:4, 20), not "just" their bodies. Death = cessation of existence, not "eternal existence in hell".
Also, you are making the expression "eternal punishment" really mean "eternal punishing". Punishing has to do with an unceasing present state of occurrence. Punishment would be in allusion to a one time process that has endless results.
It could also mean a "punishment" that comes from an "eternal God". Not that the punishing process is endless. This ideology is what makes the atheists cringe.
I'll sum up what I believe to be the correct way to view it:
"Everlasting punishment" (Matt. 25:46) is not endless punishing, nor is "everlasting destruction" (2 Thess. 1:9) endless destroying, any more than "eternal salvation" (Heb. 5:9) is endless saving, or "eternal judgment" (Heb. 6:2) is endless judging, or “eternal redemption” (Heb 9:12) is endless redeeming, or “everlasting gospel” (Rev 14:6) is endless preaching. The "eternal" pertains to the result, and not to the process. The results or consequences are eternally irrevocable. And of course, it is worthy of mention that the words “everlasting” and “eternal” in the New Testament are both translated from the same Greek word, “aionos”.
Notice that while 2 Thess. 1:9 uses the phrase "everlasting destruction", Psalms 9:5,6 says... "Thou hast destroyed the wicked, Thou hast put out their name forever and ever. O thou enemy, destructions are come to a PERPETUAL END."
So notice how "forever and ever", and "perpetual" are CONJOINED with the term "destructions" and "END". Ask yourself the question, God is LOVE is God, do the scriptures contradict themselves? Or perhaps do these scriptures provide a deeper explanation for other more difficult passages? 
God has given us the tools to crack these mysteries, and we have no excuse to not understand what God means. The Bible was written in such a way to give ROOM to those who desire to misinterpret it. As it tests people, to see how anxious they are to dig for the truth and crack the codes.
Once you put ALL the scripture pieces of the puzzle together, the truth begins to shine, and bring JOY to your soul!
This is one of the most glorious, and beautiful truths that the whole world needs to know. It is my prayer that this glorious truth of God's love and justice will transform the hearts of believers, bring tears to their eyes, and increase their apprecation for their Master and their Saviour!
God bless.
I will put it a different way then:
It is true that the root "aion" means age. But just because a root means age does not mean that every word derived from that root means a limited duration of time. For example, consider this verse that is speaking about God:
who alone possesses
immortality and dwells in unapproachable light; whom no man has seen or can see. To Him be honor and
eternal dominion! Amen, (1 Tim. 6:16)
The context is obviously dealing with God's eternal nature. The word in Greek for "immortality" is "athanatos." The Greek word for death is "thanatos." The "a" in front of the word is the negator -- without, non, etc. It means that God is deathless; hence, immortal. This is an eternal quality of God. Likewise, the verse states that God has eternal dominion. The word for "eternal" is "aionios" which is derived from the Greek root "aion" which means age. But, God is not immortal for only an "age," nor is His dominion temporal. The word "eternal" is absolutely the best way to translate the Greek "aionion" because God is immortal and eternal. Therefore, it would be wrong to translate the verse by stating that God has "aionion" dominion. Rather, He has eternal dominion.
The following two sections are verses that contain the word "aionion" which is translated as "eternal." Notice how using the word "eternal" in the first group is no problem. It is the second group with which some object. Nevertheless, the same word is used in both. See for yourself.
~John 6:47, "Truly, truly, I say to you, he who believes has eternal
(aionion) life.
~John 10:28, "and I give eternal
(aionion) life to them, and they shall never perish; and no one shall snatch them out of My hand."
~Acts 13:48, "And when the Gentiles heard this, they began rejoicing and glorifying the word of the Lord; and as many as had been appointed to eternal
(aionion) life believed."
~Romans 2:7, " to those who by perseverance in doing good seek for glory and honor and immortality, eternal
(aionion) life."
~Romans 5:21, "that, as sin reigned in death, even so grace might reign through righteousness to eternal
(aionion) life through Jesus Christ our Lord."
~Rom. 16:26, " but now is manifested, and by the Scriptures of the prophets, according to the commandment of the eternal
(aionion) God, has been made known to all the nations, leading to obedience of faith."
~Gal. 6:8, "For the one who sows to his own flesh shall from the flesh reap corruption, but the one who sows to the Spirit shall from the Spirit reap eternal
(aionion) life."
~1 Tim. 6:16, "who alone possesses immortality and dwells in unapproachable light; whom no man has seen or can see. To Him be honor and eternal
(aionion) dominion! Amen."
~1 John 1:2, "and the life was manifested, and we have seen and bear witness and proclaim to you the eternal
(aionion) life, which was with the Father and was manifested to us"
~1 John 5:11, "And the witness is this, that God has given us eternal
(aionion) life, and this life is in His Son."
~Matt. 18:8, "And if your hand or your foot causes you to stumble, cut it off and throw it from you; it is better for you to enter life crippled or lame, than having two hands or two feet, to be cast into the eternal
(aionion) fire.
~Matt. 25:41, "Then He will also say to those on His left, ‘Depart from Me, accursed ones, into the eternal
(aionion) fire which has been prepared for the devil and his angels;"
~Matt. 25:46, "And these will go away into eternal
(aionion) punishment, but the righteous into eternal
(aionion) life."
~Mark 3:29, "but whoever blasphemes against the Holy Spirit never has forgiveness, but is guilty of an eternal
(aionion) sin."
~Mark 10:30, "but that he shall receive a hundred times as much now in the present age, houses and brothers and sisters and mothers and children and farms, along with persecutions; and in the age to come, eternal
(aionion) life.
~Luke 18:30, "who shall not receive many times as much at this time and in the age to come, eternal
(aionion) life."
~2 Thess. 1:9, "And these will pay the penalty of eternal
(aionion) destruction, away from the presence of the Lord and from the glory of His power,"
~Jude 7, "Just as Sodom and Gomorrah and the cities around them, since they in the same way as these indulged in gross immorality and went after strange flesh, are exhibited as an example, in undergoing the punishment of eternal
(aionion) fire."
You can't go about picking and choosing the meaning of a word based upon your interpretations of "aion" that suits you and depending on which verse is used.
Peace and blessings to you..
