There were many schemes to redevelop the old Belle Isle building, in fact my former company looked at it one time to possibly be the new headquarters building about the time the lease was coming up for renewal. There was no good way to make office financially feasible with the environmental remediation that it was going to take along with the modifications to make it work for office.

I still think a retail/hospitality use (at that time) would have been the best hope for renovation, something like the JAX Brewery in New Orleans. Remember, what is there now is pretty much "temporary architecture" so it could be redeveloped into something else if enough storefronts go empty.

The lake was mainly the cooling water for the power plant back when it provided the power for the streetcar system.