I think Coolidge is definitely underrated even if he couldnt predict the future depression. For his time a very progressive guy (I'd say most progressive, for the day) and he understood the limits the people put on his position and held himself back to those standards. The worst thing he did was signing the Immigration Act despite his concerns raised in a sworn statement.

No man is perfect in history but in terms of even keeled presidents I think Coolidge stood out.

Not that Coolidge was an ideal to strive for. But he really did respect what he understood to be the limits placed on his position.