A lot of speculation has been going on, as well as on this forum, as in the books. The eye of the world, what is (was) it's true purpose? Some theories say it's to give Rand a buffer (Gold veines), some say it is to destroy/repair the seals. Now, I'm not sure if this has been theorized, but what if, the AOL AS knew Rand would break the seal as HF said: Clear the rubble before you build? Perhaps the EOTW's purpose was to lend Rand the strength to survive TG, to fight the dreadlords after the DO has been sealed, to fight Fain after they (together) sealed the DO. Many theory states that the EOTW was there to help in the final battle. What if the EOTW was created to help the events that will happen after the final battle? sure does give avienda's viewing of the future in Rhuidean some perspective... (BTW im drunk, don't flame me!)

I think the eye was made exactly for what it was used for, to help Rand defeat Aginor and stop a shadowspawn army from over running the boaderlands. Thus preventing the Dragon being killed and the LB being lost before it was even fought.

I think it was just a something done because of prophecy. It stored the horn, broken seal and the banner for the dragon. Not to mention helped with the first battle of the Dragon. The cost seems steep but I am sure again prophecy was at play in the decision.