Hiya. Im a bit new so im not sure if this subject has been discussed already, so let's see if this thread goes anywhere.
Just about everyone "I" talk with seems to ridicule and loathe the name "Eol". Putting aside the fact that his son pretty much brought about the fall of Gondolin, I personally find Eol to be a vigorous and sublime character. Sure he was a bit introverted and haughty, but who doesn't have there flaws? This is a kinsman of Thingol. Has a falling out with Thingol, doesn't really like the structured enviornment, moves to Nan-Elmoth. Ooh, he's so "evil". At least he doesn't hide behind his wife's magic girdle all day...
He prefers moonlight over sunlight, blah blah blah. He's open minded and can manage a congenial and profitable relationship with the dwarves. That's admirable on it's own. Get's skilled in metalwork, making a name for himself, things are looking good and darkish. Aredhel comes along. Ok, so Eol makes the forest lure her to his humble abode. Who doesn't pull all the tricks when there dating? And Aredhel's marriage to Eol was not totally "unwilling" in my opinion. He's dark, different, and doesn't like authority. This is all so new and overwhelming for Aredhel, im sure she found it inviting compared to the dull confines of Gondolin. Ironically, Aredhel switches one confined home for another, but at least there in "love". Life for the Eol clan becomes a domestic nightmare. Aredhel and Maeglin are getting antsy. Sometimes marriages don't work out. Moving way ahead now, Aredhel and Maeglin head for Gondolin. Eol pursues them, dying for an explanation. Runs into Curufin. Despite Curufin's pretentious attitude for anything non-Noldor, Eol remains calm and polite throught all the insults. Let's not forget Curufin's standing on Teleri ground, this is Eol's land, not his. Im not trying to say Eol's a victim here, but he's being pushed around like it's nobodys business. At least he didn't bring up the whole Kin-slaying thing as a counter arguement. More pursuing, gallop gallop. Fade to Turgon's throne room. Eol get's a royal smackdown. Eol has a dark premonition, this next act of his could save Beleriand, he goes for his spear, he's about to slay the anti-christ, and just when the Silmarillion could have had a happy ending, Aredhel takes the bullet for Maeglin. Turgon get's angry and stuff, Eol get's tossed of the cliff, the end. The Teleri should be crafting songs for this poor soul in my opinon. I'd like to hear everyone else's thoughts...
Funny enough, Komosot, the story I am currently writing is based on Eol's forging of Anglachel.
The first time I read the Silmarillion I found Eol to be one of the most interesting characters, and when I came to read the book again, his story was one of the parts I was most looking forward to re-reading.
My opinion of him is that he is not evil, but he is no angel either. I think he yearns for the old days when he could walk beneath the stars without any interference from the sun and the moon (if you have grown up quite happily in an age where you had neither, their appearence would have been pretty disprupting).
He seems the sort who prefers the solitude of the forests to being surrounded by people, and when the Noldor return and begin carving the land up into their kingdoms, quite rightly he sees them as trespassers.
Most of his deeds are not evil, just different. That is no crime. Aredhel, I think he perhaps held somewhat against her will, although like you said, it wasn't totally against her will. I think also, he was acting here out of misguided love, which although doesn't make matters right, also doesn't make him evil.
And so to his deeds in Gondolin. Turgon has just told him he can never leave the city and return home. To an elf who loves his solitude, this must be worse than a jail sentence in a crowded prison, and for an elf, life really is a long time.
Eol has a dark premonition, this next act of his could save Beleriand, he goes for his spear, he's about to slay the anti-christ, and just when the Silmarillion could have had a happy ending, Aredhel takes the bullet for Maeglin.
I'm not sure whether you are jesting or serious about this dark premonition. In case of the latter, Eol had no premonition, but if he were to die, he was going to take his son with him. In all of his deeds, this is the only one which I would really hold against him. It wasn't love for his son that encouraged him to give him a "mercy killing", but an act of selfish spite. Given the choice of staying or dying he chose death for himself, and he attempted to make that choice for Maeglin too.
So, in summary, he was broody and different. He made some selfish and rash acts, but was not outright evil. I'd trust him more than Celegorm and Curufin, and the deeds he committed were no where as bad as those eventually committed by his son.