Have you heard of Natural Selection 2 (/r/NS2)? It's not exactly arena shooter or is it pure FPS, but it's fast paced, require precise movement, both tracking and twitch shooting. It has steep learning curve but if you stay strong and plow trough, you will be rewarded handsomely. I am playing competitive in one of the highest division and love every minute of it. Steam link.
Edit: And it's in weekly Humble sale.
Meh, there are still active communities, and the game play itself is brilliant. There's a total conversion mod for the original Q3 engine that's completely free, and is based more in realism as far as weapons. It's called Urban Terror, and it's definitely the most fast paced realism-based FPS ever created.
I go back to it every couple of years, because it's unlike anything else. Every time I have picked up a CoD game, I always end up installing UrT.
At least give this video a watch. It's a solid example of competitive style play.
A lot of times I can't wait to play the full release so I would definitely say yes. I've recently signed up for the Chroma Alpha, which you can sign up for here.