Good topic; I'm currently researching the whole mediator teaching of JWs that Christ's covenant only applies to the 144,000 and the rest of us must simply be in good standing at the kingdom hall or be SOL. None of the scriptures quoted (insight book) to support this teaching say anything about the new covenant only consisting of the 144K. The scriptures point out that those of the new convenant are those who follow Christ and God.
Not only that, but in recent WT publications the org has been diminishing the importance of the annointed. Where does this illogical connection 144K = new covenant come from anyway?