As a 2011-2012 player I've been active through most of the memorable periods of this game, and for me personally the period between 2012/2013 - 2016 was peak AW, especially the period end2012/mid2013-2015.
During this time the game went through a lot of changes. The name Afterwind got changed into AtWar (ugh), a lot of new players started playing the game, this resulting in a lot, but I mean A LOT of new clans making the whole community explode. Because the game got shifted into like a new era, this meant that a lot of people wanted to help out within the community as much as they could, resulting in such things as the AtWar-Times Network thanks to Madara, the radio-channels and people hosting the radios, a lot of people coming up with creative things to uplift the game, the mechanics, the gameplay etc. (Un)fortunately this meant a shift in the gameplay as well, which had both its pros and cons.
During this period the map maker got introduced as well (somewhere end 2012/start of 2013), and I think thats where a lot of new players came to the game as well, giving us a very creative and fun games/maps, such as the King of the Hill-hype from Freeland (and Tunder/Ezzatam as well I think) that started somewhere in 2013, which in my opinion was one of the most fun periods I've had on this game. We saw other players like avatar and Tik-tok creating maps/scenarios that got played literally everyday. Not a day went by without seeing at least one WWII/WWI and some Ancient world games. Unfortunately I saw my favourite map: World Map, decreasing in popularity, but still a lot of people from the core playerbase hosted them from time to time, resulting in neverending games that could take up 50 to 100 turns.
The silverlight/html5 crossover is what led to a lot of players leaving the game, they didn't feel like the game felt like it did before. In my opinion, somewhere in 2014/2015 the game hit its peak and from there on it took a little bit of a nosedive, however, not as bad as the last 3/5 years. But the unsportmanslike things that people got accustomed to, such as the wf's, bigwalls, rewallls, bypassing walls, everything to like gain the advantage, is what in my opinion killed the whole 'fun-vibe' of this game.
Which is basically something I've noticed happened to a lot of games during the last 10 years or so, where sweaties just changed the whole vibe of a game..