I am by far a VERY heavy gamer. When I am tracking a game's progress, the suspense just kills me. I was on the edge of my seat waiting for the release of Thief Reboot for the longest time, and even as a beta tester I hated waiting for FFXIV to go live.
Now, that said, both examples above kept the players waiting for a LONG time, but no one was disappointed at release. Why? because the product was complete, bug free, and immersive to the fullest.
Simulation is the peak of such expectations - especially when it comes to environment and immersion. I actually vote for and HOPE and PLEAD that SCS does NOT release ATS until they feel they have a COMPLETE product that is ready to roll out. I just joined this site moments before making this post, and already I have seen debate over the release date. I would GLADLY wait until 2015, which logically at this stage, with ATS being in Alpha, would be the SOONEST we would see ATS. But regardless I would GLADLY wait to see a completed product that is stable and ready to go.
For now, e have ETS2, with a HUGE modding community, and plenty of new content between modders and DLC to keep us more than busy until then. I admit I ran out of stuff to do in ETS2 by default - then I installed TSM and bam! Much more exploring, new challenges and new sites to take in.
So my two cents - don't release until finished and don;t pull a Cryptic Studios/Perfect World/Atari and crumble under peer pressure from the community. Those companies did that and we got shoddy games and huge disappointment.