Just my opinion, if you live in Michigan and you've never experienced a "challenging deep dive", you don't dive a lot at home. 3-4 foot viz is an EXCELLENT day on some of these wrecks.
I guess that begs the question as to whether limited viz necessarily makes a dive challenging (similar to the question as to whether depth necessarily makes a dive challenging).
I've been on one dive with under 3 ft visibility (my first time in kelp, and one of my early (perhaps first) cold water dives) & a few others with ~5' visibility and did not list any of these as my most challenging dives. Frankly, the < 3ft viz dive was one of my more enjoyable dives. Easy out and back (after we got past the surf) along a wall. The lack of visibility wasn't bothering me - I just got up close and personal with all of the interesting critters along the wall. It was thumbed part way through due to limited visibility by the local divemaster I had hired to go along with me when I ended up having a spare day and no one to dive with. I would have been just fine diving for a while longer - but when the buddy says up, up we go.