It seems obvious to everyone that Fel was on to something with the seals and Tarmon Gai'don, since the breaking of the seals was the last question Rand asks on his first visit to Fel seen by us. Fel must have run with it and found out something.
But, everyone is missing the fact that Fel also had intimate knowledge of the Wheel and the Pattern (Lord of Chaos, Chapter 18, p 298-299). He actually speaks of the different Ages, and the sealing of the Bore: "It can’t be the Last Battle. Even if the Dragon Reborn seals the Dark One’s prison again AS WELL AS THE CREATOR MADE IT [emphasis mine]. Which I don’t think he can do." If we combine this with the discussion of the Ages and the note ("Have to clear rubble before you can build."), we get a very interesting picture.
Imagine this: Fel seems to know more about the turning of the Wheel than anyone so far. He understands the Pattern of Ages and the fact that the next time the Third Age comes, it must mimic the prior Third Age. Also, he understands that if the Dark One breaks free, he will destroy the Wheel and recreate time in his own image.
Here’s the point. Fel must have been on to more than just how to cleanse the taint or reseal the Bore (Rand could and is probably figuring those things out from many sources, including Lews Therin Telamon’s thoughts). So, why is it so important that he be dead that the Dark One would send a gholam (no chance of failure)? He must have discovered how to utterly DESTROY the Dark One. Not just reseal him (since the Dragon Reborn can’t do that - see above!). Maybe he got thinking about breaking the seals, thus setting the Dark One free. Then Rand can strike a fatal blow to the Dark One, and the world NEVER has to worry about him again. This, of course, would be terrifying to the Dark One, and he would immediately dispose of any possibility of Fel talking (hence, Idrien finding his limbs piled next to the desk). Nothing else really seems to do justice to all of Fel’s ideas or his cause of death (being quartered by a gholam).
wotmania says: Hmmmm... If Fel thought Rand was incapable of resealing the hole in the Dark One's prison, why would he think him capable of killing the Dark One? Obviously, though, Fel must have discovered more than the fact that breaking the seals would cleanse saidin - I think the Dark One would consider that a fair trade. Fel must have discovered something big, and if he figured out a way to kill the Dark One, that would certainly merit sending a gholam after him.
Light and darkness in harmony 
Protecting innocent damsels since 1999 
The Lone Wolf
Hey, why'd that Tolkien guy copy Robert Jordan?
I think you're on to something...