I would put it this way: alignment with CDI is as important the other major features like reactive and NIO but not more important. All the 3 features have been discussed for a long time, some already have been partially implemented. There's no reason to prefer any of them as there should be enough time for all 3 to be addressed in the next version of JAX-RS.
I have the feeling that all CDI experts in this group want is to go total CDI and spend a good portion of the next cycle's time
on getting everything injected really really well the CDI way, way better then it is already possible now, and ignore (or leave little time for) everything else that can actually inspire application developers do something new and cool in JAX-RS. While I agree that CDI-aware users should have more options to make all the bootstrapping process neater, CDI work is really not something that should take over everything else. It would take months do it right and in the end all JAX-RS users get is that they will probably be able to use JAX-RS with CDI only and no any new major features otherwise...
My preference would be for the group to go totally ballistic on doing better Reactive, Async, NIO. Make it really really well and spend all the time if the needed on this action only.