That might be more tempting to China. Remember Russia is an Oil nation.
Resell the oil, especially when Iran is so troubled selling it by itself.
It's actually a big win, since mixing good and bad oil(Russia has quite a few bad one), when possible, drastically improves product quality(and price), thus gives more profits than even reselling this very oil for market prices. Essentially it is money right out of thin air.
There are technical questions(chemical), but they are solvable.
Su-27 or su-30 are possible from Russia, but Russia has a terrible record in keeping its word and Iran has learnt this lesson the hard way. Iran also wants full ToT but this is something Russia doesn't want to give, especially not for su-30.
Yeah, that's the terrible side.
Even in Russia Israeli voice has its impact, and Iran has little way to counter such an open bullying.
+Iran is essentially out of luck, with all mutually exclusive relationships in the region, i have hard time seeing China choosing Iran over all gulf monarchies and Israel to sell offensive weapons... Iranian relations with Pakistan aren't great either.
This is why i told what maybe - just maybe! - mig-35 may be a case here. While the fighter suffers from legacy of Soviet doctrine, its downsides may actually push it forwards:
From Russian side:
1. As unwilling to sell advanced equipment to Iran as Russia is(Iran is a very well known tech absorber), RuAF doesn't really want this fighter itself. Problem is, it doesn't want Mig dead either.
2. Key russian assets aren't really endangered: Russia and its key allies fly Sukhois(and we already heard rumors what su-30sm/su-35 are unlikely to be sold to Iran even after 2020).
3. I believe it to be a fighter with the lowest possible pushback from Israel.
For all intents and purposes, even in its latest form, range/payload ratio of mig-29 family isn't great, neither are its stand off strike capabilities.
From Iranian side:
1. First and foremost, they don't really have a choice. To my belief, if China won't suddenly forget everyone around, it's the one and only modern 4.5 gen platform availible to them.
IOC 2020-2021, about as fresh as they can hope for, with all appropriate bells and whistles onboard.
2.Mig is arguably among better 4.5 gens availible for defensive counter air(primary mission), and does reasonably well most secondary ones. According to mig, most glaring shortcomings of original fighter are all fixed(namely, range, ability to acf independently of GCI environement, and a2g). And its main upsides - almost f-15 class raw performance, unmatched WVR, dispersability(mudfighter qualities) and intercept timings, all of them are still here.
While Gripen E/Meteor combo
at least shakes this position, they will never ever get it, and i am not sure if Swedish concept is even appliable to Iran and its adversaries.
3.They have much to learn from it, in two ways.
Firstly, in the end it is a really modern 4.5 gen piece. Lots of interesting tech.
Secondly, it is based on mig-29s already in their posession. It offers a an insiders vidw on how Mikoyan evolved their fighter. The same reason with China going for su-35, basically.
4.Experience with mig-29. Iran operates them for 27 years.
