The fact is the artists for WT need to follow previous drawings. In heaven all is shining so all seem white like Jesus in Revelation 1. (Yeah he's white there) So to follow from that the 144,000, must be like Christ.
You’re right that Watchtower has to follow everything it has previously stood by, they are terrified of the new and only allow ‘new light’ if they’re backed into a corner.
However Revelation 1:14 only says that Jesus hair is white. So ironically, because it is ‘like wool,’ black people (especially Rastas and that new American religion) claim Jesus is black!!