If someone either in designing team or from IAF is thinking like that, then they are biggest idiot IMHO. Its like taking away the side weapon from a rifleman since you have given him an accurate AR and tons of artillery support.
I think they might have (if) opted for GSh-30-1 is because of the weight and accuracy issue. GSh-23 which is build by OFB in India, being a double barrel, tends to be inaccurate then the single barrel GSh-30-1, which is a single barrel canon. Moreover with the range of rounds and its sheer size, the 30mm round packs more punch then the 23 mm one.