SAARC, is a chaotic organization, which is the stage for Shouting matches between India and Pakistan. The other member sit around with bemusement.
What has SAARC delivered to its members that could not have been delivered with a bi-lateral relation with India? None of the SAARC members border each other except with India.
SCO is an ambitious project, the talk of Russia-China-India axis to counter US-NATO. So, the bonds have to be a bit tighter more akin like US and Europe, they may differences but France is not going to war with US any time soon. That is not the case with SCO-India, there are too many disputes, rhetoric and posturing for domestic and international consumption.
I hope we can make it happen, but we are far away from that. There is no point joining an organization only to be shouted K A S H M I R in shangai or moscow.