It was brought to my attention that the problem with Google Maps no longer showing the “Did you mean:” suggestions in Safari is a Safari-only issue. By changing the User Agent in the Safari Debug menu it functions as expected. I first noticed this on June 18th, though it may have started before then.
Normally, when an address is misspelled or close-enough to an address Google Maps recognizes, it would offer a suggestion of the correct address on the side. This came in handy, especially for addresses in Canada, where Google Maps seems to be very picky about capitalization.
You can leave feedback for Google Maps here: http://www.google.com/support/maps/bin/request.py.