J10 is simple not powerful for air superiority fighter Iran needs,F14 can fire 6 long range BVR while TWS 24 target,there are few aircrafts today only with that power,J10 can fire at 2 simultanesly as F16,F16 can fire second long range BVR only when first became active,that mean when shit start,you need more aircrafts to cover same area...
(1) In modern combat, F-14AM upgraded AWG-9 will barely track a ~1 or <1 m2 fighter from ~100-120 KM by rough estimation. So the LR-BVR advantage is neutralized against small RCS fighters like JAS-39E, EF-2000, Rafale, F-16V, F/A-18E/F. These are the adversaries we might face before F-35 start showing up in Persian Gulf states.
(2) Meanwhile F-14 airframe itself has an RCS of 6-10 m2 which will increase if its flying with 4 x large Fakour-90 and 2 x WVR missiles. The Captor-E AESA (EF-2000 T4) or RBE2 (Rafale M) e.g. will see such a large RCS from 150+ KM away to attack it with long-range ARH Meteor BVRAAM or AIM-120D. That if they dont start jamming the AWG-9 first. F-14A/AM in IRIAF has no ECCM package on itself so it would have no chance to defend itself.
Although I am not a fan of J-10C (the operational variant) it has an AESA and ECCM package + PL-15 which has a longer range than an R-77-1.
Did you notice J10 just recently got DSI at air intakes,you need that ,ramp or other kind of airflow reducers only for aircrafts that fly over 1.7 or 1.8 mach...which mean,it was not even fast for many roles in older variant....now am not saying J10C is not good but Iran needs to have big boys,two engine air suleriority like SU 35,F15,F14...you cant replace these aircrafts with F16,J10...every country that even consider posibility of going to war maintain at least 2 types of narrow role aircrafts...USAF orders if you check their plans,consist of many aircrafts but F15 is still largest
F-15 is primarily an attack aircraft in US for quite some time now, they do not use it for aerial engagement since the advent of F-22, F-35. Not saying it can't do that but they have better tools for that like F-22, F-35, F/A-18EF. Its not just US itself, even Japanese, Koreans, Saudis, and Israelis are moving towards the smallest possible RCS fighters and all of them are owners of large F-15 fleets.
The Trends the world is moving toward are
lowest possible RCS
AESA radars with tracking ranges beyond 150 KM for fighter sized targets
ECM/ECCM
Double Duplex Tactical Data linking
Longest possible ARH BVR (AIM-120D, Meteor, Pl-15, R-37)
All-aspect WVR with no-escape zones at 50+KM (AIM-9X Blk II/III) series
IRIAF is kinda ticking many of these boxes.
,they fly F22 ...Russia also. I see Iriaf buy aircrafts like J10 or Mig 35 only as addition to SU35 or similar aircraft. IRIAF is large,it needs more than one type of aircraft anyway...but right now,priority is powerfull air superiority fighter jet ,and I can agree that it would be worth to buy J10C in addition just to get access to chinese a2a weapons,they indeed offer better range of weapons than Russians
To dominate the A2A role, the SU-35S will need a major upgrade package of following
(1) AESA radar with long track ranges, IRBIS-E is not gonna cut it with its 100 KM tracking range against small targets. Its also a PESA which is vulnerable to jamming.
(2) IRIAF will need integration of R-37 LR-BVR missiles on SU-35S to thwart the enemy from distance. The current export variant BVR Russia sells is R-77-1 ARH missile which is barely 100 KM.