Here's the conundrum:

Many of Chicago's restaurants that offer "outdoor seating" sandwich you between the sidewalk and the street. Not the most attractive option. And a lot of our waterfront places seem to be more gimmicky, where the view is a bigger draw than food.

I'd actually suggest that you consider one of Chicago's rooftop bars, most of which are connected with hotels. Great view (without the car exhaust), usually good people watching, fun vibe and some have decent food. (I draw a blank on names, but I've been to the one on Erie or Ontario'ish east of Michigan, as well as the one connected to the hotel at Northbridge.)