Thanks everyone for replying.
What TheImmortal said above, " Iranian defense contractors and military complex would LOVE to see up close and understand. ", I have actually heard this so many times in the last 5+ years from so many people whose family members are in Iran, in IRIAF or retired recently.
I guess, Iran (rightfully) feels that they have fallen behind, and hence they don't like that.Both Su35 or Su30MKI (with India's knowledge) can bring Iran much closer to the latest tech in the AF combat arena.
JF17 for Iran is a replacement, I would guess - no other way would this make any sense - for F-5s or in some cases F4s. They would NOT regard them as front line air intercept/defense but rather quick air interdiction at low cost of operation, and relatively quick adoption into service since Iran is somewhat familiar with the engine and has some background with it (RD-93).
Pakistan and the gas pipeline had nothing to do with U.S., not really. Pakistan had its own problems, and interference from Saudis, and issues with India part of the pipeline.
J10s or J16s are not a fair comparison with Jf17, not really. All of them need Russia to approve the engine sale/provision. WS-10A not available for export.
Iran will still have a few more rounds of negotiations before we find out if the source in Isfahan is correct or not.
Still believe that Iran needs to get hold of an engine of its own, and everything else it can gradually build up.
Also, of course, TheImmortal has a good point, Iran does want to take a look at a Su35/Su30 up close and personal and use it and learn from it. Hopefully not buying too many and wasting too much money. Hope they get some TOT for it also, directly.
Thanks again to all that replied.