If Shugden created disharmony and rifts, then this forum would not have existed and everyone here will be biting at each other's necks. NKT will be filled with politics and there will be partisans even within NKT. Nichiren Daishonin who started the Nichiren school of Buddhism in Japan built the foundations of his tradition by criticizing other Buddhist traditions during his time. The result of that was that over time, 1000 years later, his tradition split a total of 4 times: Nichiren, Nichiren Shu, Nichiren Shoshu, and now Sokka Gakkai. Each of these traditions are clean cut from each other although the base teachings are the same. Not too long ago Sokka Gakkai and Nichiren Shoshu was embroiled in legal battles and Sokka Gakkai used to be the lay division of Nichiren Shoshu. If NKT becomes like this then yes, Dorje Shugden is partisan but if they are still together then it proves that Dorje Shugden does not and cannot split the sangha as what some people claim. I am not saying that Nichiren is bad or wrong, but that is the method he chose to spread the Dharma and that is the result. Different masters will use different methods to do so.
The monks of Shar Ganden and Serpom are still together and they have not splitted from each other. That is more than enough proof to show that Dorje Shugden does not cause any disharmony or whatever. In fact his entourage Namkha Barzin is said to help the monastery grow by causing harmony amongst the sangha in the monastery. So where does all these partisan things come from? Is there definite proof of Dorje Shugden causing disharmony? I have not seen it if there is. The Ban caused obvious disharmony, it was fine before.
Geshe Keslang is targeting the western and educated people so if he used oracles it would not appeal to some people in that area of the world. So he has to change his methods and approach. I don't see anything wrong with that. It can't be that someone who has written so many books on sutra and tantra, and who has over 1000 centers in the world be negative. So he had to stop using them to suit the minds of his students. As for the current Trijang Rinpoche, perhaps he would not want to interrupt the current incarnation's works or it would be too dangerous. Or even, that it could be hard to accept by some of his students and he does not wish to disturb their minds. Just like a mother knows what's best for her child, a Guru always knows what's best for their students so we are not in a position to judge.
Regarding the isolation of NKT from other centers, it is because they can do it and they have enough people and support to be self sustaining. That is why NKT called themselves new kadampa instead of gelug because they are a new tradition altogether rather than a part of gelugpa. Even if GKG did not practice Dorje Shugden but he had to spread Dharma on such a great scale in the west, he would still do what he is doing today, I believe. I am not too comfortable with NKT as well but I am not judging because if GKG is bad and wrong, it would also mean that Trijang Rinpoche is an ineffective teacher to produce such students. So that is not possible.
Also as TK reminded in another thread, please be sensitive to the NKT posters in this forum. Please consider their feelings and samaya to their Guru.