Both of you have points that should be considered. If they're going to take F-15EX and Rafale, why should Flankers still being kept. It will create logistical nightmare if they have to maintain F-15, F-16, Flankers, Rafale, Hawk, TA-50 and Tucano. 7 type in Inventory will be a nightmare logistically even for Large AF standard.
However in same time considering the situation of Fighters inventory and the need for quantity, I do see on why they will try to upgrade existing Fighters along side new procurement. Ideally if they want to go with US/French combination, they should get rid or rundown both Flankers and Hawk. Perhaps they can sell those Flankers to Vietnam, and use the fund that can be save on maintaining Flankers to upgrade all existing F-16 or getting new LCA in form of FA-50.
Personally I also don't see why decision on taking F-15EX, asside some prestigious show case (which still embedded in mind of MinDef and TNI thinking). They should go with F-16V and Rafale. US offer of F-16V actually not because they don't want to offer more capable fighters (as many Indonesian forumers accuse), however more to logical steps considering TNI-AU situation. However seems now US also understand, logical thinking is not always the main driver for Indonesian MinDef.
Thus back to the choices of F-15EX and Rafale, and the law that demand Indonesian Industry participation on defense procurement. Let's see how far Boeing and Dasault off set deals will cover for work share with Indonesian Industries.
F-15EX fleet is replacing/continuing our F-16 fleet as the only US fighters in Indonesian Air Force.
Don't be surprised if Dasault come with offer for Indonesia to get out from KFX/IFX program with Korea. They will offer instead plan to build 3 sq of IFX, why don't you build 3 sq of Rafale on top the 36 that have order. Similar deal as what Brazil got with SAAB, can be part of the deal that Dasault can offer. If that happen, it could be Rafale that's going to replace existing F-16 in future.
Is it going to be that on the offer ? Can't say that now, but French media already speculating that. So will have to see.
One thing for sure, IFX is not own by DI and it's basically as I have mentioned so many times in this forum, is an under license deal between DI with KAI. Thus if DI got under license agreement with Dasault, for the purpose of their learning curve, it is going to give the same effect. IFX main IP rights is belong to KAI (don't have any illusion that DI will have main IP rights for IFX). In fact what Embrear got from SAAB for Gripen NG Under License deal is better than What DI have on IFX. For one thing, Embrear already have Rights to sell Gripen NG for South America market, while DI still not having rights to export IFX anywhere.
In conclusion, what off set deals that will be offer by Boeing or Dasault, will play on final decision on which Aircraft that can have more future with Indonesian AF. After all the law for off set works on Indonesian Industries will still going to take part.