The ex TGIE are already being silenced and the clear indiction of that is the drastic name change to Tibetan Central Administration. They are no longer TGIE after 50 years of exile. Their so called Prime Minister Lobsang Sangye is not a Prime Minister but a Central Administrator now. What govt in the world would be humiliated into changing their names into that of a Administration?! It is absurd and shows a huge loss of power.
Their bans, alienation of their great masters, intrigues, poltics, bad decisions, short-sightedness and sheer pettiness has gotten nowhere. The ageing Dalai Lama has resigned from his job does not foretell of good things to come. If you are doing so well, why are you resigning? Obviously pressure from the Indian govt.
Traditionally each of the four sects of Tibetan Buddhism have special practices unique of their own schools not practiced by other schools or not as 'popular'. Although not practiced by another school, it does not mean the practice is not effective or not respected. It is not necessary for all schools to accept a particular practice to validate any practice.
Some examples of practices focussed within their own schools and not so widespread in other schools:
1. Lamdre of the Sakya not in other schools
2. Vajrakilaya within the Nyingma not so much in Gelug
3. Lam Rim within Gelug not in other schools
But each is a valid practice but not very much practiced in other schools.
Shugden may or may not become accepted in other schools of Tibetan Buddhism. It does not matter. If one great well known lama promotes Shugden, He will grow in the world to many non-Tibetans. Great lamas are the key for growth of a practice. And there are many great lamas of the Gelug School promoting the practice of Shugden for sure.
TK