Alright, let me just say: It's a great game. It's got good design, fun gameplay, and nice graphics.
HOWEVER: Hawken's Dev team is pretty much completely disbanded. You won't get any form of support, updates, etc. from the dev team because the dev team no longer exists. Ingame purchases with the premium currency also won't really work.
HOWEVER: Despite being unoffically dead, the community is still active, the game is balanced and fun, and its good enough that you can continue playing it. The "EPIC MANUEVER" feeling of tricking someone into attacking a hologram, then going up behind them and letting loose with a rifle is more then enough to keep you playing. Not only that, but the game's F2P model allows you to actually unlock everything related to gameplay (IE, not cosmetics) simply by playing the game. You can unlock all the mechs with the non-premium ingame currency.
The general statement: Yes, its dead. Yes, you won't get any support from the Devs. However, it's still active, and its still fun.