Server Restarts
AoC has so much potential for server restarts, so many world changing and social variables that can form the world in different ways each time.
It's a better alternative than just piling on expansions because what happens is the world gets bloated, or too large, quickly, and requires more players, which the network foundation can't support. It raises the level cap which eventually means they have to trivialize many aspects of how leveling was originally designed, if you start an alt or you're a new player.
It's ashes and more of a sandbox, but it's supposedly also has themepark aspects so what I just said will happen if the game isn't redesigned in some ways.
I mean if it's done right it can work, but it's just a cascade of problems that happen very quickly. With server restarts(for games that accommodate them like AoC) you can still add content, but you can also do things in "seasons" like Path of Exile does, where with each ladder reset new things are added and if they work really well they stay, if they don't they're gone the next season.
This allows them to rework/add to the game gradually. You know I think of WoW Cataclysm when I talk about this, the game had gotten to the point where so many expansions were added that the increased xp and the added ways to getting faster xp had trivialized so much of the game, messed so much up, the world was already getting too large and empty and it had gotten old enough that they just had to come in and majorly rework everything all at once.
And I know that's a large part of why so many people left. Not only did they not do it well, the change was too much too fast(probably part of it not being done well). That happened pretty quick too, from the start of WoW until Cataclysm.
I'm explaining myself on this because some people I've talked to are very against server restarts and I got a feeling this is a widely held notion with MMORPGs.
I know the game is set up already for a form of reset with sieges, but that doesn't solve many issues and it would be much more fitting if it just served as a mechanism to encourage short term "resets" so that a complete reset could be very far in-between, I'd imagine like 1 year resets. I'd also imagine a large portion of servers will not engage in sieges and if any do happen they'll be from small groups of people against the majority of the server who have teamed up.
It just depends on how the game is tuned. I can't imagine achievements would reset, transmog collections would reset, freehold skins would reset, flying mounts die anyways, and mounts collections surely aren't going to be a life long struggle like in other games and have combat skills so aren't conducive to a reset(I think mounts should not be items, should stay in the world and be limited as far as possession quantity since they have combat skills and it would be much better gameplay that way, but that's a different story).
If server resets are a thing they also make a player think about time invested in something and how they want to build up. I think there should be more than ample time for a casual player to realy dig in, the reset should be on the side of casual players.