There have been a few bills introduced over the last 2 years to rescind or modify the ban, but things seem to be heating up as of late.
What kind of impact have you seen in the places you frequent? Over the time the ban's been in effect, I've mostly only gone out to the Crofoot/Pike Room, and they had banned smoking at some (if not most) events even before the statewide measure kicked in.
for some recent developments, here's a smoky link:
http://www.lansingstatejournal.com/viewart/20120430/NEWS01/304300026/Michigan-smoking-ban-still-hot-issue