Simply put, before you go marketing and advertising, you need to make the barrier to entry MUCH lower.
Relative to 99% of games, Legions has a high skill curve before it becomes "fun". However, there are a number of ways to lower the barrier of entry for random people. All these ideas for new reticles, new maps, random new features, are not going to make the slightest difference in number of people who join and number of people the game retains. No one joins or quits a game because of no-fog, so why worry about it now?
First of all, I'd write a troubleshooting FAQ for installation. It should be pretty easy, since there aren't many errors, but it shouldn't be a requirement for someone who wants to play to have to install mIRC or TS3. I recall that I was launching the wrong launcher, so whenever I tried to join a server, it would give me an error message. Hell, just telling someone how to open the console would already be a step up.
Second, the ratio of vets to newbies is too high. Right now, it might be 1:2, meaning, on average, newbies in a pub server have a high interaction rate with vets. If you bring in a ton of randoms, and change the ratio to 1:20, there'll be less negative interaction, and create a more conducive learning environment. Of course, if that's the route you take, you need to have the capacity to host all these people, and be aware of the natural skill progression people are going to take and be ready to accommodate (honestly, I'm talking about PUs).
That leads me to what I see as the fundamental problem of the competition scene. There needs to be a "tournament mode" on servers that can be voted, and some sort of admin power that is held by more people. The idea of 16 people waiting in TeamSpeak for 2 hours for one of the devs to come start up a server that can't even be accessed from the server list is absurd. And regardless of how much advertising you do, there's no way that can fly for long at all.
There's ZERO reason someone should have to join mIRC and/or TS3 to get involved in PUs.
Marketing: Find some way for Legions to go viral. Whether it's finding people like this:
http://www.tribalwar.com/forums/showthread.php?t=621322, or doing paid advertising, or writing a series of well-targeted articles hailing a new release and timing them in conjunction with gameplay videos. Opening up the game to modding (if possible) would also invite independent ideas and effort.