Water levels are actually up from last year by 4-6". Depths are not really a problem. We draw 4'-6", most of the channels on the inside of the islands and shoals are 6-8 ft. deep and more. I rarely run into any spot that I get nervous and have to watch the chartplotter carefully.
The Bay out of Midland and Penetang are plenty deep and out to Giants Tomb / Beckwith has lots of deep water. You do have to watch where you're going as there are areas in clear open water that have shoals below the water, not to mention the constant flow of boat traffic. Once you get out close to Giants it thins out enough that you can relax for a while. One good thing about the gas prices is the bigger boats are tending to stick closer to Midland
The inside channels are well marked and sounded and you won't have any problems. Only real issue is further north above Parry Sound, which is a days motor / sail away.