India is up and coming and I feel that it be in the best to join in with this seeing the prime minister sikh, outside India the khalistan movement is stronger - I mean alot of kids are taught about it and they were not even born in 1984. Some may find this dangerous as they are only taught one side of things.
Secondly not all sikhs support this split, during a debate at university I met with fellow sikh brothers and other Indians (Punjabi and not) and not one thought it was a good idea. The non sikhs said it will lead to trouble from other states wishing self rule. One guy hit the nail firmly on the head and I could not answer this as I feel he had a point - If you want a khalistan then ask for your part from Pakistan first (as Guru Nanaks birth place is there).
Other reasons were that India is a secular country and also the fact that Punjab is mixed and what will happen to non-sikhs e.g. Hindus, Christians, Bhuddists, Nirankaris, Ravidasias, Muslims, etc.
Raj Khere Khalsa - this saying did come true but sadly its in the past, the sikh empire is no more, but look at this philosophically the moughal empire ended, the british empire ended.. its the cycle of life.