I don't think we have enough heavy fighters. Not when we will be facing 500 flankers, 500 j-10's vs 270 flankers and 36 Rafales. We also need a bunch of standoff weaponry which the f-15 offers with LRASM,jasmm-er and more. Only problem being the f-15 can't supercruise unlike the Rafale otherwise the f-15 is the strongest contendor apart from Rafale. The typhoons aesa doesn't exist. The Gripen is basically mk 2 with lesser payload capacity, the f-16 is outdated. The f-18 is too ugly and can't fly. The f-15 literally has the largest radar among all fighters in the western world and has a GaN based EW suite. The f4 I assume will also get GaN based avionics.F15 is a heavy air superiority fighter which will have higher operational costs and lower availability compared to either Rafale or SH. That's why it's better to invest in more MKI if we want similar capabilities. But we have more or less enough of those. That's why both Su35 and F15 won't make the cut.
A combo of Rafale's and f-15ex will solve all problem on the western border and it's enough to deter the Chinese psychologically. After which we can peacefully focus on getting the mk 2 and tedbf online.

Easily will be able handle two front war. The f-15's replace the mig-27's,mig 23's and jaguars. While the Rafale's replace the mig 29. The mk 2 replaces the mirage and mig 21.