Please quantify your threat perception.We are faced with 2 N armed neighbours with whom we've fought wars & have long pending unresolved issues.I'm sure France didn't break down the equation into the simple one you've formulated however powerful a fighter Rafale is ( Note - I'm not denying it's efficacy ) .Please weigh that against China's & Pakistan's air forces including future acquisitions in the period between 2019-26.
In fact , beginning next year when we begin mothballing the MIG 27 ( already dead as they rarely fly out on patrol duty ) till 2030 when the aircraft we're retiring will be much more than the ones we're inducting , will form one of the most critical periods in the life of the IAF.God forbid ,if we were to get into a conflict situation , we haven't even tied up with major power to loan their aircrafts. This reflects the depth in our strategic planning .
I'm merely pointing out & supporting
@eldarlmari post that our replacements when they start coming in the form of the Tejas ( Mk 1 , 1a & (2??) ) , Rafale & FGFA seems too little , too late.