Before FOC certification (2019) Tejas was in no way ready to replace anything.I would disagree. In the short run, IAF is suffering because they still rely on Mig-21s and have not replaced the MIG-27s.
Unless you believe those 30-40 year old obsolete jets are better than Tejas Mk-1/1As, the air force has shot themselves in the foot thanks to their disdain for Indian products and love of phoren maal. We should have had half a dozen squadrons ordered and inducted by now, and would have cost just a few billion dollars. Woukd they be as good as the latest Gripens and Rafales? No. But they would be a match for anything the PAF has, full up squadrons and far better than what the IAF has stubbornly stuck with.
And suggesting that IAF should have waited for Tejas mj 2 is a familiar trick. Demand the perfect to avoid ordering the good, because phoren is best.
The tejas mk1a orders were given while the tejas production line was still running till ADA gives them something that fulfills the original ASQR.
Why should the airforce have wasted money on the IOC tejas ?