IA is refining the CSD; this time the term CSD is missing. Its like CSD v1.1 in the form of a new doctrine.
The previous one wasn't CSD, it was simply called "proactive strategy".
CSD is happening now with the new reforms.
Also, even though the IBG will be smaller than a Division but it will be commanded by an officer (Major Gen, 2-Star) who is supposed to command a Division. Now, this relates to an educated guess that the formations under command of an IBG can swell up to a Division strength at some point, and for this task a Brigadier might not be suitable.
Logically, if 10 IBGs are raised and 5 are used to attack, then the remaining 5 will become the reserve. So yes, an IBG can easily become division sized.
One IBG can even be reinforced by more IBGs if necessary. Of course, one of the Strike Corps can also take advantage of any successful IBG.
Based on your plan, if the 10 IBGs manage to distract 10-15 PA divisions, then the Strike Corps are gonna have a significantly easier time.
Another point is mentioning gunships in IBG's, so far India has used Mi-24 and converted Mi-17's into gunships, but now with the induction of AH-64's, the scenario will look very different and has chances to tilt in India's favour. To protect the IBG's and gunship's IA will call in IAF support and the integration between three services has been mentioned which means PAF will be on the defensive also. All this happening, when the main attack has not even started.
IA plans to operate 60 Rudras, 114 LCH and 39 Apache at the minimum through the AAC making it unnecessary for the IA to ask the IAF to reinforce them with their gunships. So you can expect the IBGs to be integrated with the AAC's gunships right from the start.
IA is the main customer of both Rudra and LCH, not the IAF.
Such an offensive will have higher success rate because majority of IA armor, mechanised infantry and other forces would be used in the IBG attack, and the forces left behind in that sector would mostly be infantry formations, probably in defensive posture.
IBGs will be raised from the Pivot Corps. The Strike Corps will remain untouched. So the IBGs will not have the majority of armour and mechanised infantry. In fact, you can expect the IBGs to have at best 1 regiment of tanks each, so it's not a lot when you consider 10 regiments out of a total of 62 tank regiments.