4K - buy now or wait for next year's edition?

The 4K editions have been very well received. Next year, there's a 4k "ultimate collector's edition" coming out, which will include both trilogies and "bonus material". I have no desire to own The Hobbit trilogy on 4K but I wonder what said bonus material will be. If it's extra scenes in the extended LOTR movies I'll definitely wait for next year's edition. Does anyone know what the "bonus material" will be?