I think the problem with resale is the dual nature of the law, the law was written to allow private people sell their old stuff at will, if someone wants to put a stack of books out for sale during a flea-market they should be able too, if someone wants to do the same with their old games, they should be able too. And too a lesser extent you've got used book stores, selling products that publishers have stopped printing.
The problem comes into it when you have an entire industry pop up, like with Gamestop, that does it's level best to cut out the publisher; Selling the product once, then buying it back, selling it again, then buying it back again... So personally I'd be happy if stores like Gamestop were forced by law to kick back a chunk of used-game sales, within say the first 6 months after the release of a game, to the publisher.