My personal choise for ground attack was SU-24/25, with license build by HAL instead of Jaguar and MIG-27/23 but its a history now, and if that would have been the case, than we might think of SU-34, but now since we are already inducting Rafale, their is no need to induct another platform to have the similar capability, with the overhead of maintenance, spares, training and cost.
Its not modification of MKI, rather the deep upgradation process, which would involved AESA Bars upgrade, Internal EW jammer, up gradation and strengthening of airframe, and engine, and MAWS installation, which has become must to survive the modern combat.
BARS AESA upgrade, would add the capability of the MKI to do interleave operation of A2A and A2G simultaneously, and add the A2G attack capability, making it true Multirole fighter plane from the Air Defence/ Air Superiority fighter plane, with an edge of tangem seat with an extra pilot, to share the work load.