I started playing FAF 2 months ago, so I consider myself still somewhat of a new player. What I found/still find very challenging and frustrating:
- Joining a community and finding players to play with is HARD. There is a clan system in place, but actually finding and joining one of those clans is very difficult, as nearly all clans do not post contact/recruitment data publicly. Even a recruitment section here on the forum would go a long way of fixing this issue.
- 1v1 ladder is punishing and winning offers a lot less rewards than other RTS games. The gamification of the ladder rating system is basically non-existent. Other games (starcraft 2, LoL) do a better job here at motivating you to play by pitching you against similarly ranked players in a division.
- initial setup of hotkeys and mods could be even more 'out of the box' than it currently is. I remember I had to spend a couple hours at the start setting up /refining hotkey assignments. Things like this should just be set to sensible defaults in my oppinion.
- Teamgames, astro crater, survival maps and dual gap are all great fun for a beginner, as it feels like a lot less punishing environment, and more like a place where you can explore and have a good time. But getting into a game is frustrating, as lobby hosts will happily have you sit around for 20 minutes to fill their game up, only to kick you in the last second because gray=gay.