Well, there are only 21 77W frames with new J, including the 9 with the new F suites. And for ULH you need at least two frames. So that sort of limits the number of new J destinations.
For those interested: one can look at the 'route tracker on The EK Source ? Emirates News and Information to see the frames which have been used on any route (the default is the last 4 weeks). A6-EPV onwards have new J, A6-EQH onwards have new F (and new J). Although this is no guarantee, one gets a feel for what frames are used. For my 'home base', CPT, you will see that the pilots are usually called Wilbur and Orville, we almost always get EB or EC frames