The side-objective of Tejas project will be to rival the mainstay fighters of PAF and PLAAF at the time. In the case of PAF, currently Mk1 rivals Blk2 and soon it'll be Mk1A vs Blk3. Whether they'll come across in a battle in irrelevant.
Mk1 and Mk1A cannot rival the latest mainstay of PLAAF, which is J10C. That's where Mk2 comes in. Obviously, India is years behind China and will keep playing catch up. But there'll be years of overlap.
I think that J10C (or upgrade) in PAF is a good possibility as well, since fifth gen won't be numerous and Blk3 will still be light.