Better and clearer documentation.
Finding relevant information regarding server rules, setting, and mechanical changes is alot harder then it should be. This is one of the most common issues new players have voiced to me.
Make it easier to get into the server.
Finding quests, stores, consumables, where to sell stuff, and in generally "learning" the server is a lot harder then it should be without someone taking you in hand and guiding you through the process. Having all the merchants concentrated around a market where people can easily find them, instead of in half dozen different places would go along way towards helping as an example.
Shift away from looking down on solo content.
CoA is a multiplayer game, we all get that. But sometimes there are not enough people online, either allies or in general, to do stuff with. And having solo content can mean the difference between a player logging out and playing another server and/or game, or staying IG long enough for more players to log online. And if it helps them earn gold, potions or xp in the process of staving off boredom all the better.
Grant more attention to pc plots, and focus on empowering players.
The threshold for getting dm attention and support for personal plot lines, or for factional plot lines is at times very high. Its understandable that dms will not be as interested or inspired by all player plots, but the players involved will be. And they will do stuff to support and push it forward. A little support goes along way. Focusing too much on dm plots can lead to situations where players log IG for events but otherwise don't really do much otherwise because while the events themselves are enjoyable the plot as a whole does not grab them, save for a few players trying to use it as a way to gain faction promotion and trying desperately to get others to help them.
On the topic of empowering players, I really think that even in a setting with powerful and established npcs players should feel like they matter. That they are a real driving force. On a basic level its hard to feel that way when most interaction with npcs IG or on the forums is them trolling, mocking, putting down, or otherwise telling you that you are not worth their attention. Its also hard to get players to take initiative if they need to constantly "phone home to mommy" to ask if something is okay before proceeding. I also think npcs are far too eager and quick to shut down player actions and plans only further highlighting that players are subordinates to npcs they server at the whims of.
Less focus on "earning it" at the expense of fun.
I understand the principle behind wanting players to earn the perks they obtain, but the threshold is so high that it essentially rules casual and newer players out. Also things like perma death events to accomplish major progress while enjoyable to a portion of the server are toxic to the rest, and tend to lead to lulls of varying lengths after each mass pc death event where alot of server and story momentum has been sucked out from CoA, and takes time to rebuild itself. This only adds to the threshold present in "earning" stuff.
Is letting fun and cool stuff happen even if they have not been fully "earned" really such a bad thing if it leads to players logging in, and staying IG having fun? Essentially lowering the threshold. Also, the concept of earning something seems to be different depending what dm you talk to. For others its showing high degree of mechanical competance and surviving an event. For others its involving lots of people into a plot. And for others its playing a high energy balls to the walls concept that makes lots of enemies and stirs up conflict, at times for no other reason then the sake of conflict.
Scale down challenge
While not a personal issue for me, something that I hear alot in conversations with other players is that CoA is too hard, the death penalty too harsh and stuff like the xp nerf simply not fun. Balancing server so its challenging for a small handful of top players (that will thrive regardless) only serves to make things sadistically hard for others, especially players new to the server and/or the game. There is a middle ground between Hello Kitty Island Adventures, and Dark/demonsouls that should be found.
Advertise and be active on social media.
Be active on both GoG, and Reddit NwN forums. Post videos about CoA on youtube. Screen shots of key/cool events on twitter. GoG runs sales of nwn a couple times a year and each time new fresh players either find the game for the first time or return to it. Other servers have swelled by being able to reach these players. There is no reason coa should not be able to do the same.