Umm an Indian Mig-21 did shoot down a Pakistani Atlantique MPA in 1999 & the 21 does have a decent combat record keeping in mind its limitations.Nyway,I get ur point...though throwing out all the Migs will create a huge logistical gap.Upgrading the 27s & 29s seems to be sensible & thats what the IAF is doing.The SuperHornet looks very likely,unless the Indo-US N-deal fails which will then open the gates for the French Rafale or EF-2000,along with probably a few Russian Mig-35s.
The Mig-21 actually has decent number of kills, as well has a huge number of losses, but I do not consider it recent, it is from the 60s. Still I agree, it was a solid enough machine in its time, although now it is rather dated. I believe it is the last MIG to have any kills, and really was the end of the MIGs, things have gone down hill fast since then. I agree you cannot get rid of them all right now, but I do not think the IAF should put too much money in them. Even Russia is puling MIGs from service, replacing them with Flankers where possible. Especially with the "teen series" and flankers out there, MIGs just are not competitive anymore, the 29 has a 0-12 record, it has proved worthless against falcons, eagles and flankers. I think India should go with the new Hornet as it is better priced and more versatile then the Rafale and Eurofighter, and it is very doubtful the 35 will be produced at all, the program has been plagued by problems, and most funding has been cut. And its capabilities are dubious at best.