I had never done the Peace Council before. In the past I had either completed the civil war quest before that point, or had almost completed it, and opted to finish it instead of doing the peace council. I had assumed that it was something as simple as walking up to both sides, asking for a truce, and them saying yes. I was quite surprised when we met on top of High Hrothgar and started negotiating for territories. Lots of great lines.

I also went ahead and tried various scenarios to see what the results are:

1. All options result in a truce - no side will walk away no matter how bad the deal.

2. If you kick Elewen out of the conference, you can side with the Empire on every other single decision, and Ulfric will agree. You can give both Riften and Winterhold to the Empire with Tullius still complaining that he is getting a bad deal. Apparently Ulfric REALLY hates Elewen and that is all he really wants to agree to a truce.

What parts of Skyrim did you not discover until a much later playthrough?

I have never done the peace council either. Someday I want to, since it sounds interesting. I haven't taken thieves guild past the first meeting with Karliah, haven't done more than a couple DB quests and have not advanced the main quest beyond meeting Parthy. Haven't completed Dawngaurd as a vampire hunter and have not completed Dragonborn's main quest past the first trip to Herma's realm.

Gosh, it sounds like I haven't really played the game, but I probably have well over 1,000 hours in the game with about 30 different characters, some of whom made it to level 49, some were DiD characters that died rather quickly. I played every week between 2011 and 2012 on PS3, then sporadic playing on Xbox off and on from 2013 to 2015. Most recently, I have about 50 hours into a modded game on the PC.

The key to whether or not there will be a truce conference or not hinges on where the Dragonborn is in the main Dragon quest line. It must be after the Dragon quest has started (killing the dragon at the Western Watchtower) and after the DB has visited High Hrothgar (to meet the Greybeards and discern that they are totally neutral on the civil war), and before Alduin has been killed.

I find that even after 3500 hours of gameplay, I still keep finding stuff I never encountered before.

Interesting on how some of you have never done the Peace Council, me I've never *not* done it. The whole Civil War dust up really bores me on both sides to the point where I've only done the Imperials once just to see how it plays out in the base game and I've never done the Stormcloak side. So with the Civil War always in a stalemate in my games, any character that advances that far in the main quest will inevitably end up babysitting the two sides by focusing them on the real problem by doing the council.

I've also never completed the Dark Brotherhood quest line, got part of the way into it on one character and then just lost interest in his roleplay story as it wasn't working out too well. Perhaps I'll try again at some point as I would like to see how it all plays out.

I've never done the Companions questline. Am currently doing it now. Its a little dull so this will be the only time.
My last character completed the thieves guild where I'd never before gotten further than Brynjolf's initial, unavoidable 'meeting.'
I've never done most of the daedric quests. The ones i have done are Meridia, Azura, Dagon (does that count?) and Peryite, oh and Mora, of course.
I've not completed the CW on the Imperial side.
Never been Thane of Riften. Never bought the house in Riften. I hate Riften, lol.
There's likely lots of other little quests I've never bothered with, I don't remember them all.

I haven't done the civil war on the Imperial side. I haven't done Dawnguard on the Vampire side (but I plan to do it in my next game). I've done about half of the Daedric quests and two-thirds of the side and miscellaneous quests.

This is much closer to full completion than I've come in any of the other games in the series. I actually enjoy Skyrim's quests and NPCs quite a lot.

Not sure what platform you are on, but Civil War Overhaul mod by Apollo Down makes the CW dynamic, fun and different from play through to play through based on your choices. Cool thing is the mod uses material never implemented by BGS; so much missed due to a release date.

http://www.nexusmods.com/skyrim/mods/37216/? link for your convenience.

I've done the peace conference a few times but didn't pay as close attention as the OP. I did, however, notice that some imperial or stormcloack camps can disapear. That was a bummer as I would use some of these camps as 'safe' spots to spend the night (there's a fire, lots of soldiers, a teather for your horse, and you can even grab a hay pile and sleep). Also, depending on who you side with, the disposition of the other side changes. I used to trade with all the quartermasters but after the peace council, only one side was available. I believe some forts occupied with bandits came under military control as well. So be careful, you can change the map complexion in subtle ways.