It actually gives the same return as one wishing well, if that article is correct. So you are in fact saving 11 squares of space by replacing a hedge maze with one.Some people are less keen on Hedge Mazes, don't be put off them! Compared to 2 Wishing Wells the Hedge Maze occupies an additional 2 squares of real estate, but offers the same returns, and provides more victory points.
On balance, to dismiss the Hedge Maze as a new player's folly, is short-sighted. By all means, once you have dozens of wishing wells in your inventory, you may no longer wish to use a hedge maze, but remember all you'll get back is 2 squares of real estate, and you'll lose victory points.
Before someone jumps in and starts shouting about wishing well shrink kits, yes I do know about these, and yes they do make your wishing well smaller, and thus if you have two of these and two wishing wells with which to replace a hedge maze you probably have moved on anyway. Never be afraid to upgrade, there was nothing wrong with the Pottery when you first founded your city.