
Not necessarily.... IF the buy affords them to have cash left over elsewhere.
While less capable than most foreign jets being evaluated, the Tejas is said to have its strengths. Low observable airframe, ease of maintenance, reliable engine and high sortie rate. If they can deliver that economically, it'll go a long way toward giving them a nice medium strike platform, with some limited self defence capabilities and most importantly - numbers. Where the IAF is woefully under-served is in having even a rudimentary stealth capability.
I think the Indians know J-20's vs. SU-30MKI's (however much they're upgraded), isn't going to end well. Further, China is fielding at least one (maybe 2) stealth fighters, and is known to be working on 2 stealth bombers. Add to that fact they're working with PAK on co-developing its own medium fighters, and... that's a problem. To this, India has.... no answer. That's the much bigger problem, IMO...