These are one off situations. Here the IA used their transport helis while IAF used everything else.
Giving IA fighters will mean the ATC will have IA as well as IAF controllers. How on earth are they to coordinate traffic and combat requirements? It will be a big mess. Even the USMC operate from their own airbases separated from the USAF. They don't share a base. The USMC is tiny as well.
Atc is IAF controlled and in combat situation Aircraft of both IA & IAF can operate without probs,
In Kargil war IAF was doing Dual jobs.
1. Working on its own Airstratergy ( PGM strikes, CAP )..
2. Also giving CAS ( Calls made by men on ground )..
For that it required different aircraft s on same airfield ( MIG-21/27/29, JAGS & MIR-2000 ) Now think abt the mess was then ( In the mess usually IAF found itself helpless providing CAS and the delays kicked in )..
Now suppose IA had a squadron of SU-25, It can be used for CAS and its deployment would be faster to IAF & It would be a relief for IAF to operate on its own strategy against enemy Ground and Air assets..
For ATC it would be not very different for giving instruction to IAF JAG or IA SU-25s..
IA & IAF have very good relations with-each other, Besides i am saying IA should have at least a few ( 3 ) squadrons for CAS on front-lines..