I think you'll like Chicago. I did it in 2005 and it was a great experience. Just be careful in the opening miles. It can be a bit easy to get yourself out a bit too fast.
Honestly, I don't think it's fair to judge an event based on such an extreme as we saw last year. With that many people and that extreme weather, I don't think any amount of organizational planning could have had anyone ready for what happened. Look at how highly regarded that race has been for so long. It didn't get that reputation by not running a tight ship.