The lack of lore knowledge of many of the posters is showing
- it's been a while but if I remember right... this is what they mean:
To kill Man is to reach Heaven, from where we came before the Doom Drum's iniquity. When we accomplish this, we can escape the mockery and long shame of the Material Prison.
According to the elves (and, quite likely holds some truth) the elves were like daedra, immortal - the creation of the material world, and man brought them down from their immortal state and they still blame the races of man to this day.
1) Erase the Upstart Talos from the mythic. His presence fortifies the Wheel of the Convention, and binds our souls to this plane.
The divines are what make the material realm what it is, and it appears that belief makes them what they are - removing belief in a god will weaken it's existance and weaken it's control over reality in theory. Talos, as the man-god reinforces mankind's hold and power over the material world, if the elves are to ever return things to the mythic era state first thing that has to go is talos).
2) Remove Man not just from the world, but from the Pattern of Possibility, so that the very idea of them can be forgotten and thereby never again repeated.
Not entirely clear on the meaning, but the elves think man was largely responsible for their mortality. It's inevitable they want man gone - in a timeless world you REALLY have to make sure they're erased. If you looped back through time to a point mankind existed again you'd be back to square one.
3) With Talos and the Sons of Talos removed, the Dragon will become ours to unbind. The world of mortals will be over. The Dragon will uncoil his hold on the stagnancy of linear time and move as Free Serpent again, moving through the Aether without measure or burden, spilling time along the innumerable roads we once travelled. And with that we will regain the mantle of the imperishable spirit.
As I explained earlier, the divines make the world what it is. Prior to the material world's existance where the divines bound themselves and set their rules, things like "time" were not linear, akatosh is probably the single most important figure because the world as we know it is entirely dependant on time moving in a linear, predictable fashion - this is the bedrock of everything else in the mortal world. Evidentlly they believe that in removing mankind's grip on the plane, they'll be able to unlock akatosh's connection too which'd be the first step to moving the world back into a timeless, non linear state (Look up the "http://www.uesp.net/wiki/Lore:Dragon_Break" for an example of what happened the last time they tried to break akatosh's hold on the mortal realm).