e-dawg said:
I wonder if the FCC can make a waiver for 106.7 since 105.9 was able to move to Willis Tower with 106.3 in Lansing IL
Nope. As Dave explains in his answer just above, there are two sets of rules at play here. For stations that existed and were already short-spaced before 1964, the FCC has essentially "made a waiver" - there's a whole set of fairly loose grandfathered rules at play. In particular, there's no second-adjacent spacing requirement, which is why 105.9 didn't have to concern itself with 106.3 in Lansing or with 105.5 in Valpo. For stations like 106.7 that signed on after 1964, the rules are the rules.
(That lack of second-adjacent restriction is why K-Love has been able to move 94.3 in from Elgin and why Univision has been able to move 93.5 in from Joliet.)
Even pre-1964 grandfathered stations (like 92.3, but not 106.7) still have some rules they must follow, though. They have to fully protect any station that signed on after 1964, or that was fully spaced in 1964. And they can't increase overall interference to or from other pre-1964 stations on the same or first-adjacent channels. That's the hitch with moving 92.3: it's locked into place by its existing grandfathered overlap with 92.5 in De Kalb. I'd have to look more closely to be certain, but it's very possible that 92.3 and 92.7 Arlington Heights are locked into place against each other as well - they may have been fully spaced against each other in 1964, which means they have to continue to respect the current second-adjacent rules.
(Back to those 93.5 and 94.3 moves: if the only considerations for those moves had been spacing to WXRT, WLIT and WLS-FM, 93.5 and 94.3 could have moved all the way in to Sears and Willis. But there's also the IF-spacing rule that keeps 93.5 a certain distance away from 104.3, and 94.3 from 105.1, and those rules don't have any grandfathering exception. And there's spacing to other stations that aren't pre-1964 grandfathered, which requires a certain minimum distance between, for instance, WJKL and WZOC in Plymouth, Indiana.)
The spacings around Chicago and the midwest aren't as bad as in the northeast corridor, where just about everything's locked into place by mutual short-spacing - but it's a pretty solid bet at this point that anything in Chicagoland that could have been moved by now has been moved. Some of those moves have been pretty impressive, too - 107.9, for instance.