First and foremost risk is serious unrest in Jammu and Kashmir especially in the valley. The attitude of Omar Abdullah proves that he along with other political parties will definitely provoke the people of Jammu and Kashmir, as if they are being bereft of a natural and fundamental privilege. The mob psychology never understands whose privilege is it? Is it the privilege of ruling class of J and K or the common citizen, the horrible episode of violent protests including stone pelting could return to streets of valley!
The separatists along with terrorist outfits would also put themselves in a final war! Innocents would suffer a lot. Pakistan on the other hand would do everything to provoke the people of Kashmir, apart from its attempt to internationalize the issue!
Back home also, anti-BJP parties and especially anti-Modi politicians can stage demonstrations accusing Modi government for inducing fire in the valley. There are also legal hurdles! Both from Kashmir and main land, people may knock Supreme Court's door questioning authenticity of such abrogation!
I foresee that to deliver a verdict on this issue, a full Constitutional bench of Supreme Court would be involved. It would depend how much time they will take to deliver the verdict. Till that time may be J and K has to put under Presidential rule and curfew might be a regular phenomenon in the valley. Terrorist attack in rest of India is also not ruled out. Thus there would be a full blown proxy war!
I believe Narendra Modi too is realizing the consequences of such a step. He would be wise if he takes sufficient preventive measures before taking step toward abrogation of article-370. Also the danger is, if the Constitutional Bench of Supreme court gives adverse verdict on repeal of this article, where would credibility of Narendra Modi stand! That means he has to do a lot of legal counseling with Constitutional effort!
I feel the first step by Modi government would be rehabilitation of Kashmiri Pandits inside valley with sufficient security. Second would be rigorous negotiation with some of valley people who are not of separatist mindset. Third is putting anti-terrorism mechanism both in Kashmir and rest of India! Fourth is building excellent relations with global powers including China! Fifth is making our defence system very strong to face a possible war from Pakistan! Above all, Modi has to deliver his promise of good governance, development and growth to the public at least in a year to prove himself a committed and credible leader of India!
Thus looking all the above, I think Modi wouldn’t touch Article 370 for an year or two! He is not a kind of leader who does anything whimsically without preparation to face the consequences! Thus there is significant risk as well as requirement of reasonable preparatory period to initiate anything!
Therefore I don’t think any action on Article 370 would be done visibly by Modi government before 2017! But yes back-channel talks, all type of preparation may have started even before his swearing in! Narendra Modi is said to be a very minute planner who plans even at micro level! Thus one can expect action on Article 370 but not so early!