I would agree it isn't a classic, but I'd still rate a re-release of Prince of Persia above a dozen other steelbooks zavvi have that you can read about here on HDN. As zavvi have those steelbooks, I think Prince of Persia deserves a re-release. The price they sell for on ebay would - I think - indicate a re-release is in order.
I also think it's fair so say that we've passed the point where zavvi steelbooks are limited commodity. I'm sure zavvi don't say 'OK, we aren't releasing any more steelbooks until these sell out'. They'll make whatever sells. So if you have steelbooks you want to see released, make a noise about it.