Yes I am. With aircraft service lives approaching 50 years keeping healthy payload margins is sound flexible design. And yes munitions are growing smaller as well as larger and heavier. See the MKI for an example - it could carry from SDB types to Brahmos without any structural changes needed.
I'm getting the feeling that I'm repeating things and you're not reading - the design is done for the ASR and whatever payload it requires. if the ASR requires a certain payload to be carried on different hardpoints, the designers will deliver structure that can sustain the load*1.5 times that for 9Gs or whatever your max G load is supposed to be. If you left margin, then you'd be considered an amateur, since adding to the empty weight of an aircraft is a big no no. Adding that to cater to future growth is not done at all. Develop a future block, and add a more powerful engine so that the T/W ratio doesn't get affected badly, but don't hobble an airplane with extra strength and weight when it is over and above the ASR's requirements. Doing anything else would be amateur in fact.
You cannot wake up 10 years later and suddenly up your payload requirements and expect that no design changes are required. If it was anyone's fault, it was the IAF who thought that a single R-60 would suffice for the outermost pylon. Even back in the late 1980s, they had better CCMs in service that weighed a lot more.
The world over, if an aircraft's hardpoint has to carry higher weight than it was stressed for, it has needed redesign. Even the F-16 has gone through several strengthening exercises for each Block which have added weight to its original lightweight structure. Only saving grace has been a higher thrust engine then being added on.
And no, the Su-30MKI cannot carry the Brahmos without strengthening.
If you don't keep some margins you end up with a farce - for example necessitating a new wing being designed because of new short-range is AAM is heavier than the previous. We just got lucky the requirement switch to a heavier AAM came during the prolonged development. Otherwise we might have had a fleet of 250 aircraft that could only carry obsolete missiles on outboard pylons or none at all.
That is what ASRs are for- to specify what the weight of the weapons you intend to carry are. No one says ok, lets add another 100 kg weight to the ASR specification just so that say 10 years down the line they may get a heavier missile to hang off that hardpoint. That way you'd end up being significantly higher weight than the original design goal would've been.
Those added loads are usually fairly easy to calculate and compensate - if I may say so as a layman - lead to fairly trivial weight increases in the larger scheme of things. The wing flex tolerances and what the increased outboard weight does to them are the interesting and harder part. The wings wont break off or anything drastic like that, but service life takes a drastic hit.
No they're not easy to calculate and compensate. It may lead to a lot of revalidation and rework.