Now, on topic, at what the non trollers have been saying. I'm just amazed why common sense is going for a toss here. The number of people who are saying that it will be obsolete! What on earth are you all talking about? Please check out how many fighters the IAF needs, and how many we will get in the next ten years (other than LCA), and how many will retire. If you do that simple calculation, you would be urging HAL to set up two production lines instead of one.
We need a bare minimum of 750 fighters (39.5 squadrons). Other than 272 MKIs and 189 rafales, what else? And those 189 rafales won't be here until 2022. We have about 260+ fighters that need to be replaced before 2020. Which aircrafts will provide numbers?
Can we afford 400+ Rafales or MKIs? Even if we shell out the money, would we want such expensive assets doing CAP and point interception for the bulk of their useful lives? Make no mistake, any air force the size of India's will need hundreds of light fighters. There is n other way.
AMCA does not even exist as a non flyable prototype. So forget that bogey of "moving on to AMCA". That plane will NOT arrive in the next 15 years in operational service. Any country would take that long to design, test and put a 5th gen aircraft in production. USA would, Russia would, China would. India would too. At least.
Both our adversaries and most of the world will be flying LCA class aircrafts for the next few decades. Only small air forces like Britain's or France' can afford to have the entire force comprised of Rafales or EFs. Any country that is not as rich as USA, and needs a very large number of squadrons, will fly a lot of light fighters. China does, India does. And will.
And by the way, it is quite ironic that the IAF will fly mig 21s and mig 27s upto 2018 or so, and then claim that LCA may not be advanced enough for tomorrow's LOW END needs. While LCA is in service, the IAF, PLAAF and PAF will all be flying fighters that are less sophisticated than it.
It's about numbers. We want 39-42 squadrons, right? Then we need 180+ LCAs. Can't afford to double the number of rafales or MKIs. Or FGFAs. Most light duties will have to be born by a light fighter. We are not the USA, our defence budget is a fraction of a percent of theirs.