This is how they explain it in the insight book, they explain that praying through Jesus in prayer is because of his role as High Priest, not as our mediator.
<<There are, thus, others not of the 144,000 “sealed” ones who also pray to Jehovah God in the name of Christ, putting faith in the merit of his ransom sacrifice. This sacrifice is not only for those for whom Jesus mediates the new covenant but also for all mankind expressing faith in Christ. (1Jo 2:2) These not in the new covenant also appreciate that “there is not another name under heaven that has been given among men by which we must get saved.” (Ac 4:12) They, too, look to Jesus Christ as their great heavenly High Priest, through whom they can approach God and through whose ministration they can get forgiveness of sin. (Heb 4:14-16) Revelation 21:22-24 points out that ‘the nations will walk in the light of New Jerusalem,’ where Jehovah God is the light and the Lamb Jesus Christ is the lamp.>>
Earlier on in this discussion they explain that Jesus has different roles, one as a mediator and one as a High Priest
<<Holding the offices of Mediator and High Priest, Jesus Christ, being immortal, is always alive and able to plead for those of spiritual Israel approaching God through him, so that he can mediate the new covenant until those persons receiving his mediatorial assistance are saved completely. (Heb 7:24, 25) He is able to conduct matters to the successful completion of the new covenant. Those in the covenant are eventually installed in the heavenly priesthood as underpriests with Christ, their great High Priest.—Re 5:9, 10; 20:6.>>
This is a doctrine that they rarely discuss. Most JWs have no idea that Jesus is not considered to be their mediator and it would appear that the GB would like to keep it that way unless they can somehow find new light to bring all JWs into this mediatorship. Given that the other sheep are now considered to be part of the household or domestics in the Faithful & Discreet Slave parable I can see this as a possibility. Also, when they introduced the new light about types and antitypes they explained that they generally would not be holding onto this idea that there are distinctions between who is being spoken of, the other sheep or the little flock.