I'm no loyer either, but from my seat on the periphery of the entertainment industry, I agree with
radagastly -- I wager that Middle-earth rights will be tied up for many a long year to come.
The Hobbit, for instance, is not expected to enter the U.S. public domain until 2032 at the earliest. I'm not sure how a book that's part of a larger setting like this is affected -- releasing Middle-earth and hobbits would arguably infringe on LotR, which would still be protected for another seventeen or eighteen years.
I'd say a greater danger to Middle-earth -- if in fact it really
is a danger -- is the possibility that control of the Estate will fall into the hands of a less fastidious custodian than Christopher following his death.
There are movements afoot to extend copyright indefinitely, mostly so that corporations like Disney can continue to profit forever from certain big money-makers like Mickey Mouse. Even a cursory search on the web will reveal strong opposition to this movement. A short story called
"Melancholy Elephants" by Spider Robinson sums up the views of the opposition.