Numbers are not always important, but, if Indian govt. has some reservation, regarding numbers, they can increase the number of seats in each IIT. I think it would be a much more practical solution. To raise an REC to the IIT standard, would definitely, dilute govt. attention towards present IITs. Since, all the present IITs are very strong, in terms of infrastructure and has enough scalability to accomodate more seats.
So, don't go for numbers, as "Everything that can be counted, not necessarily counts".